When attempting purchases through the Epic Games Store using you saved Xsolla Credit Card, there is a known error that causes the transaction to not complete. We are aware of this problem and are working on resolving it in a timely manner.
If you would still like to use the payment method, you can remove the Xsolla Credit Card from your Epic account and try your purchase again.
To remove the payment method, go to the payments section in your Epic Account and click the trash can icon next to the payment method you wish to remove.
If this does not resolve the problem, please contact support.