account not closed.

My husband had a cheque account with standard bank. Also a savings account and a funeral policy, He went into Standard bank to close all these accounts. The savings account and funeral account was closed but never the cheque account. Now we are getting phone calls saying we owe R2900 from Lawyer's. How can that be if he closed the account, signed all the paperwork and they still took his cards from him? It's not accepted as it is not our fault. This was 2 or 3 years ago. We lost the paperwork due too a move.