How to unlock my Apple Cash account

For instructions for a locked Apple Cash account, see the following from: If Apple Cash is restricted or locked - Apple Support

If your Apple Cash account is locked

Your account may be locked if there's suspected fraud on the account, or if additional security checks need to be completed. If your account is locked, you can't use Apple Cash to make purchases, send or receive money, add money to your account, or transfer money to your bank.

If your account is locked and there are no instructions provided, contact Apple Support.

This is primarily a user-to-user support forum; other Apple users like you.