# How to Block a Customer on Shopify by Phone Number or Email > How to block a phone number or email from verifying cash on delivery orders on Shopify with Cartsaver's Blocked Contacts list, what blocking stops, and how to unblock a contact. URL: https://cartsaver.net/help/block-customers-on-shopify-by-phone-or-email/ Updated: 2026-10-24 **Blocking a customer on Shopify with Cartsaver means adding their phone number or email to the Blocked Contacts list, so Cartsaver stops sending them verification codes and WhatsApp order confirmations. With cash on delivery shown only to verified customers, a blocked contact cannot verify, so cannot place a COD order.** The outcome: the same fake buyer stops costing you a courier trip every week. It is for Shopify stores selling on cash on delivery that keep seeing the same numbers behind refused parcels, prank orders or abuse. Shopify’s standard admin has no setting that stops one phone number from checking out with cash on delivery, so merchants end up cancelling the same person’s orders by hand. Cartsaver is a Built for Shopify app by Xtnd that confirms cash on delivery orders on WhatsApp or SMS before you ship, then uses the same WhatsApp conversation for order updates, abandoned cart recovery, one-tap cross-sells, reviews and campaigns, through the official WhatsApp Business API. Inside the app this feature is the **Blocked Contacts** page (menu name: **Block Contacts**). ## What does blocking a contact stop? Cartsaver checks the Blocked Contacts list before it sends a verification code, a WhatsApp order confirmation or an order follow-up. If the phone number or email is on the list, nothing is sent, so the contact can never be verified. | Flow | What happens to a blocked contact | | --- | --- | | [Pre-checkout OTP verification](https://cartsaver.net/help/pre-checkout-otp-verification/) | No code by WhatsApp, SMS or email, so the customer cannot verify. With Restrict COD to Verified Customers on, cash on delivery never appears for them. | | [Fast Checkout](https://cartsaver.net/help/fast-checkout-with-otp-verification/) | No code, so a COD order that requires a verified contact cannot be placed. | | [WhatsApp order confirmation](https://cartsaver.net/help/stop-fake-cod-orders-with-one-tap-whatsapp-confirmation/) | The order is created in Shopify, but no confirmation is sent. It stays unverified, and your Pending Order Action marks it high risk or cancels it when the wait time ends. | | Order follow-up (reviews and Buy Again) | No review request or Buy Again message is sent. | Blocking is about verification, not about every message. Order update notifications, abandoned cart reminders and campaigns do not check the list. Each blocked attempt to verify is recorded in Cartsaver’s Logs with a delivery error, so you can see the contact tried again. ## How do you block a customer on Shopify with Cartsaver? Open the Block Contacts page, choose Phone Number or Email, enter the contact and click Block Contact. You can also block a contact in one click from the Logs page. Blocking takes effect for the next code or confirmation. ### From the Block Contacts page 1. In the Cartsaver app menu, open **Block Contacts**. 2. Under **Block New Contact**, pick the **Phone Number** or **Email** tab. 3. For a phone number, choose the **Country** (for example Egypt (+20)), then type the **Phone Number** without the country code. For an email, type the **Email Address**. 4. Click **Block Contact**. The contact appears in the list with the date in **Blocked At**. The Blocked Contacts page: block a phone number with its country, or an email address. ### From the Logs page 1. Open **Logs** in Cartsaver and go to the **OTP Verification** or **Order Notification** tab. 2. Find the order or code that looks fake, then click the **⋯** (more actions) button next to the recipient. 3. Click **Block**. Cartsaver confirms that the contact has been blocked. The Logs page, where each recipient has a more actions menu with Block. Blocking from the Logs is the faster habit: when a parcel comes back refused, look the order up in the Logs and block the number from the same row. ## How do you unblock a contact? On the Block Contacts page, search for the number or email, then click **Unblock** next to it. To unblock several at once, tick them (or **Select all**) and click **Unblock Selected**. Unblocking works straight away: the next code or confirmation is sent as usual. ## When should you block a customer? Block a contact when you have clear evidence: several refused parcels, orders placed with obviously fake names, or abuse in the chat. Don’t block after a single missed delivery; real customers miss couriers too, and a blocked real customer simply stops being able to order on COD. A good routine for a COD store: - **Once a week,** list the orders your courier returned and check them against the Logs. - **Block repeat offenders** from the Logs, one click per number. - **Keep the rest of your protection on:** WhatsApp order confirmation with a Pending Order Action, and cash on delivery restricted to verified customers. Blocking catches the people you already know; [fake COD order protection](https://cartsaver.net/help/fake-cod-order-protection/) catches the ones you don’t. ## What blocking does not do - **It matches the exact contact.** A customer who comes back with a different phone number or email is not blocked. Verification still has to confirm that new number is real. - **It does not hide your store.** A blocked contact can still browse your store, and, depending on your verification settings, may still pay online by card or wallet, which carries no COD risk. - **It does not cancel past orders.** Orders that already exist stay as they are; cancel them in Shopify if you need to. - **It does not stop every message.** Order updates, abandoned cart reminders and campaigns are not filtered by the list. ## A worked example A fashion store in Cairo uses pre-checkout verification with cash on delivery restricted to verified customers. Its courier returns three parcels in two weeks from the same number, each refused at the door. The owner opens Logs, finds the number on the OTP Verification tab, and clicks Block from the more actions menu. The next time that number tries to order, the verification pop-up cannot send a code, so cash on delivery never appears for it; the Logs show the blocked attempt. A month later the same person tries with a new number; that number has to verify like anyone else, and the store keeps an eye on it. ## Common mistakes - **Blocking without restricting COD.** With pre-checkout verification, turn on Restrict COD to Verified Customers. Otherwise a customer who cannot verify may still be able to choose cash on delivery at checkout. - **No Pending Order Action with WhatsApp confirmation.** A blocked contact’s order is never confirmed. Set the Pending Order Action so it is flagged or cancelled instead of waiting in your queue. - **Typing the country code twice.** Pick the country from the list and enter the number without it. - **Blocking on a hunch.** Check the Logs and your courier’s returns first. If a customer says they never got a code, check the Blocked Contacts list before anything else; the [Cartsaver troubleshooting guide](https://cartsaver.net/help/troubleshooting-guide/) and the docs page [OTP not received](https://docs.cartsaver.net/troubleshooting/otp-not-received/) cover the other causes. See every [Fake Order Protection feature on the homepage](https://cartsaver.net/#feature-fake-order-protection). ## Frequently asked questions ### Can you block a customer on Shopify? Shopify’s standard admin has no setting that stops a specific phone number from ordering with cash on delivery. With Cartsaver you add the phone number or email to the Blocked Contacts list; the contact then gets no verification codes or WhatsApp confirmations, so it cannot be verified for COD. ### Can I block an email address as well as a phone number? Yes. The Block New Contact form has a Phone Number tab and an Email tab. Blocked emails stop receiving verification codes by email. ### Does the blocked customer see that they are blocked? They are not sent a message saying so. They simply do not receive a code or a confirmation, and the blocked attempt is recorded in your Logs. ### What happens to a WhatsApp order confirmation for a blocked number? The order is created in Shopify, but no confirmation is sent. It stays unverified and follows your Pending Order Action: marked high risk or cancelled when the wait time ends. ### Can I unblock a contact later? Yes. Click Unblock next to the contact on the Block Contacts page, or select several and click Unblock Selected. The next code or confirmation is sent normally. ### Which plan includes Blocked Contacts? Every plan, including Free. Blocking does not use any messages.