Debit orders don't go off when they should

I've had a data contract with Telkom for over 5 years, and the debit orders went off when they were supposed to go off and I never had an issue. Then when time comes to upgrade, and now the debit order becomes a problem. Every month since October last year, they fail to take the debit order. Telkom has a 20 day payment defualt handover policy, so you can expect to hear from the DebtCollectors 20 days after the invoice was not paid, with no curtesy call from Telkom to inform you that there was an issue. Every single month I get messages and calls from the DebtCollectors, I have to pay the invoice manually, I phone Telkom to sort it out and next month we repeat the cycle. I've accepted no less than 3 debit order mandates, and not one of them is working. This month I phone Telkom before the DebtCollectors do, and I am told I am not outstanding at all, and the next day I get a call from the DebtCollectors telling me they handed me over for overdue payments. At this point, it's less hassle to just cancel the data package and sit with the minor inconvenience of no data when the wifi is down.