Unable to close/stop business debit order 2 years!

After more than two years later after porting of lines to another supplier, we are still being invoiced, billed and a debit order deducted from our bank account.<br> <br> Several emails and holding on the line for hours and passed from John to Jane we still have no resolve.<br> <br> No emails get answered and no department can resolve the account!! Service is non existent and this is *****ing as MTN is taking money for a service they are not delivering!!