Bad service

My husband has many issues with Telkom. The debit order should go off on a date. When it comes to thw date the debit order doesn't run. This month their excuse is that my husband's bank rejected the debit order. How is this even possible if the debit order has been going off monthly from the same bank account. They are quick to suspend and charge extra but not quick to reverse it. We have been Telkom Talking for a while and never had this issue since this year