Hello,
Thank you for contacting Rank Math and bringing your concern to our attention. I’m sorry for any inconvenience this issue may have caused you.
Please make sure that the flag during checkout is showing the correct country at the top right corner. Here’s an example screenshot:

If you are trying to validate data while accessing the website from a different location, you need to force the change of country in the dropdown.
Lastly, if you are using a Proxy or VPN, please disable that and use your actual ISP to update your payment method.
If the issue still persists, please clear your browser’s cache or try using a different internet browser to purchase.
Let us know how this goes.
Thank you.
Yes,
No VPN and proxy is on my laptop and no flag is shown during checkout.
Not able to buy premimum
Hello,
Please try in a different browser and make sure that pop-ups are allowed by your browser so the checkout screen can appear.
Don’t hesitate to get in touch if you have any other questions.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.