Hi, @tayyabbukhari! Thanks for reaching out in our Community Forums and for sharing your concern, I’d be happy to help.
Businesses based in the United Kingdom can use Shopify Payments to accept Visa, Mastercard, American Express, Maestro, Discover, Diners Club, and UnionPay debit and credit cards. Since you're experiencing issues, I suggest activating test mode and using the test credit cards to simulate payments. You can then select the Mastercard test card to proceed with your order.
If a customer reports an issue, you can review your orders timeline to learn more about the payment method and details regarding the issue. It's always suggested that they reach out to their payment provider to ensure that the card is ready for online purchases.
We’d also be happy to continue assisting you through the available contact methods in our Help Center. Once you're there, log in to your account, select a topic, and scroll down to the bottom of the page to select a contact option.
Let me know how that goes!
Mac | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog