How to Block a Phone Number on Shopify
A phone number is one of the hardest details for a fraudster to change. Here's how to block one at checkout on Shopify, in any format, so they can't come back with a new email.
Short answer
Shopify has no setting to block a phone number at checkout. Ongoing Defender does it in one step: add the number to your checkout rules and it's blocked in any format, so +61 412 345 678, 0412 345 678 and 0061 412 345 678 are all caught.
Why block the phone number
Email addresses take seconds to create. Phone numbers don't, so people who've been blocked by email usually come back with the same number. Blocking it closes the door they'd use next.
| Situation | Why the phone matters |
|---|---|
| Fake cash-on-delivery orders | The number used to arrange delivery stays the same across fake names |
| Repeat chargebacks | A new email after every dispute, but the same phone |
| Card testing | One number reused across many attempts |
| Someone you've banned | A new account, but the number they've always used |
How to do it with Ongoing Defender
- 1Install Ongoing Defender and turn on Checkout rules.
- 2Add the phone number to your checkout rules. Type it however you like.
- 3Or search for the customer and block their account, email and phone together in one click. You can also do this from their page in Shopify admin with More actions > Block at checkout.
- 4Write the message blocked buyers see.
- 5Test a checkout with the number typed a different way to see it caught.
Blocked buyers see no payment or shipping options, just your message, on every checkout including Shop Pay, Apple Pay and Google Pay.
Matched in any format
Buyers type phone numbers in dozens of ways. Defender compares the digits themselves, across national and international formats, so one rule covers every version of the number.
- With or without spaces, dashes and brackets.
- With a country code like +61, or a 00 prefix like 0061.
- With or without the leading zero, so 0412 345 678 matches +61 412 345 678.
- UK and French formats are covered too.
Block numbers automatically when they keep trying
Turn on Stop repeated checkout attempts, and Defender counts checkouts per phone number as well as per email and address. After 5 checkouts with the same number within 60 minutes, the number is blocked automatically and marked Added automatically. You can change both numbers.
Why Ongoing Defender instead of Shopify's built-in tools
| What you need | Shopify on its own | With Ongoing Defender |
|---|---|---|
| Block a phone number at checkout | Not built in | One rule, in any format |
| Block a buyer's account, email and phone together | Not built in | One click from customer search or their page in Shopify admin |
| Block numbers used in repeated attempts | Not built in | Automatic, after 5 checkouts in 60 minutes or your own limit |
| Work with any payment provider | Fraud Control rules need Shopify Payments | Yes |
Tips for best results
- Block the shipping address along with the phone. Together they're very hard to replace.
- For fake cash-on-delivery orders, the phone number is usually the best single detail to block.
- If a number is a shared business line, use Test a checkout to check it won't catch other customers.
- Look over automatic blocks now and then, and remove any you no longer need.
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