Bad service unauthorised debit order.

Mweb is debiting my account every month for a service that was never rendered I ordered a router which was never delivered now Mweb is deducting R299 and I need to pay bank charges to reverse this debit order, I have called numerous times and I was told that there is nothing to cancel because my account was cancelled so I need to why am debited if I have not account with Mweb.