pay fee after closing account

Credit card companies can charge fees for a closed account. Your mother should make sure that she pays off the balance of the debt asap and does not get hit with a residual interest.

Hi,
Welcome to the forums!
I think the credit card company is charging fee as your mother still has outstanding balance on the cards. If your mother is making payments on the outstanding bills, then she must be receiving processed bills from the credit card company. The credit card company is charging fee to cover the processing expenses.

All fees and interest will continue until the account is paid in full. Closing the account simply prevents new charges from being made. If your mother is having a difficult time paying the account, I would suggest she contact the lender to see if they could put her on a hardship plan. Generally, all fees are waived, interest is reduced and payments are lowered once enrolled.