It sounds like the bank authorization is completing successfully, but Minecraft is not receiving the confirmation from the payment process. Since you have already tried multiple cards and your bank confirmed there is no issue on their side, contacting Microsoft Support under Billing and Account Profile seems like the right next step.
You could also try signing out and back into the Microsoft account, checking that your payment method and account region are correct, and restarting Minecraft before attempting the trial again. Hopefully Microsoft Support can identify the pending transaction or subscription issue from their side.