Telkom the ******* with bad customer service

We have an internet/wifi and mobile account with Telkom. We had the internet first and they took off their money for that just fine in the beginning.The problem came when I got the mobile phone and they combined the payments.They apparently tried to debit the bank account and the payment bounced back.The bank had no idea why that happened because there was enough money in the account and when I called Telkom they had a different bank account number.So somehow there must of been some ***** up on their side because the account details was still the same.I then gave them the right account info and sent them a bank statement to show that there was enough funds in the account so they can fix their mistake and credit back the R200 something fee they charged.They then proceeded to debit money from the account before the debit order date without asking me.I am very angry as this could lead to a bad credit score if there wasn't enough funds this time!!! And up until now they haven't rep**** to my complaint or refunded the extra charge!