a cancelled cresit card is still accruing fees

I have a cancelled standard bank credit card, and then received a call threatening legal action for two transactions that occurred at least 12 months after my card was closed. Brooks and Luyts attorneys have been threatening action even after they agreed to investigate. In short standard bank claim that I am responsible for those deductions (which were old debit orders) whereas i believe they should simply have been declined. this issue has been ongoing since April and even when I go into a branch to deal with it, they can not find my account ( because it is cancelled)