This is not something Apple can fix. Something has triggered the account restriction as required by Federal Banking Regulations. This is not something Apple support can resolve.
Please follow the steps in the support article linked below.
If Apple Cash is restricted or locked - Apple Support
Apple Cash is a service that’s administered by Green Dot Bank. Contact an Apple Cash Specialist at Green Dot Bank by calling (877)-233-8552 or by calling 1-800-MY-APPLE