closed credit card re-open by imitating principal holder

Hi,

My mom has a credit card (principal) and my aunt was under her (secondary).

My mom decided to close her credit card account because of personal issues (another story).

Weeks after my mom found out that my aunt re-open her closed account via the customer support without my mom's knowledge. Apparently, my aunt re-open her account as pretending to be my mom.

The next banking day, my mom immediately close my aunt's account again. When my mom ask the bank if my aunt can open the account again, the bank said that since my aunt knows my mom's personal info then she probably can.

Now, what should we do?

Send an email or better a letter with proof receipt to the bank stating that you are permanently closing the account due to fraud committed by a third person and that if you were to re-open, it should be done personally at their bank with due presentation of proof of identity.

thank you for your reply.

my mom just called the bank's customer support and they said that the account is already tagged or noted as fraud. they gave an assurance that the account won't be open again.