Incorrect billing - No movement

Someone from Cell C sales department called me just before my contract ended offering me a special deal. We confirmed the product and price clearly over the phone and it was delivered to me some days later. However when my first bill came it was almost double what we agreed upon. I called customer service and logged a query. More than three weeks and several calls later I had to pay the incorrect amount AGAIN and every single time I call thay report that someone will call me back within the hour after they listen to the recording.<br> <br> It feels like they are only stalling until I give up. Either you correct the bill or you come and collect the phone.