Billing and bad service

In 2014 I bought iPhone5 only to find out that it was faulty and I had to return it back to the nearest Telkom dealer,and I opted for iPhone6. To date Telkom is still billing me for two phones.IPhone6 and the iPhone 5 I returned.Every month telkom is taking either R1500 or R 2000 really !! and I have to run to the bank to reverse the money and this is creating a bad record for me and every time you call they will tell you that the case has been escalated to the back office.I have being trying to sort this out but in vain my case number is ***2 and ***0 this is the third year I'm really diappointed