Change of debit order details

I phoned the Telkom call centre in August to update my banking details. They did not update them and the debit order went off the incorrect account. I phoned them again at the end of August requesting that they update my banking details. They still didn't update my details and debited the wrong account at the end of September. I then phoned them again and tweeted about this, they promised to update so I decided to block Telkom debit orders on my account. I see they tried to debit my account at the end of October. IS IT REALLY THAT DIFFICULT TO CHANGE A CLIENT'S DEBIT ORDER DETAILS??? So I've done an EFT and that's how I'll be paying my account until you update the details!