Deleted credit card &1 for inc. payments in acct &2, partner &3

What causes this issue?

The credit card details &V1& in the business partner were deleted. They
are still being used in contract account &V2& however, with partner
&V3& for incoming payments.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Use the pushbutton situated to the right of this line to go to
maintenance of the contract account &V2&. Choose another credit card
for incoming payments for the business partner and transfer these
changes.
The changes are then saved when you save the current business partner.

Error message extract from SAP system. Copyright SAP SE.