Incorrect Limits set

On renewing our contract more than a year ago we requested limits to be set on two numbers. When receiving the bill I realised that no limits was put on these numbers.I also noted that even though we took out sky packages on the other two numbers we were also charged extra for additional data use even though all should be included. I then requested limits to be set on these numbers via phone calls and emails to MTN business all to no avail. I was still billed incorrectly. I therefor want to be reimbursed with the money that was deducted off my banking account because of additional charges that was charged to our account without our authorisation and in contrary of our contract. This has been more than a year and I have not received any phone call from any credit controller to reimburse me with my money and to even remotely try and resolve this matter.