Hi MATTHEWGEILING,
You started from a great resource: If your Apple Cash account is restricted or locked
Regarding the issue, if the information below found in the same article doesn't resolve your issue you'll want to reach out to Apple Support directly to further assist.
"If your Apple Cash account is restricted
Your account may be restricted if your identity verification fails multiple times, if there are multiple accounts tied to the same social security number, or if there's suspected fraud on the account. If your account is restricted, you can still transfer your Apple Cash balance to your bank or use it to make purchases with Apple Pay. You can't send or receive money, or add money to your account.
If your account is restricted and there are no instructions provided, contact Apple Support."
To contact Apple Support directly use the links below.
Contact - Official Apple Support
Contact Apple for support and service - Apple Support
Best.