Overcharging for 4 months

Telekom is unable to get themselves sorted out. I signed up for a Smart Home Advanced package of R570 per month. All was going well until they promised to upgrade me to uncapped for an extra R200 per month at the Rage Expo in Oct 2014. In my next bill I discovered that they were actually charging R286 per month extra. I then cancelled the uncapped and asked to be reverted back to my Smart Home Advanced. In my next bill, I discovered that they started charging me for Do Advanced at R756 per month. On 14th Jan I called them and asked to fix it and reverse it. I received no response even after calling every 3 days until the 16th of Feb. Somebody then decided to reverse only one month's charges (out of 4 months), but then when the next bill arrived, I was still billed for Do Advance. I have now logged my 4th dispute and after many escalations, am still waiting for someone to call me and give me feedback. Nobody seems to know what they're doing and nobody is calling me to give me good or bad news even after promising to call every time. You are in breach of contract, so I am withholding payments until you resolve my queries. I am even considering terminating all my business with you.