Very bad service and over charging on data

I have been a customer with Altech for 2 years .Late last year I was billed R800 for data usage. I had raised the matter with the company and was promised the matter is being looked at and someone will come back to me once done. I am not sure if I am impatient but that someone has not come to me yet. My contract expired early this year and before expiry I went to Sandton branch to upgrade and amazingly I was told that my account has been upgraded already with a Samsung Galaxy. I then asked to be connected to the company's call centre where I explained my situation. As usual the same song was sung for me \matter is being looked at and someone will come back to you once done". Until now that someone has not come to me. I usually check my data balance before I do anything and a day after I had used bundles. As at 31 July it showed that I had around 500MB which I had not used and amazingly I received a bill for July that shows an out of bundle amount of over R 1 000. I phoned the company twice inquiring about the bill and was told someone will come back to me and since then nobody has ever come to me. Altech's service is excellently very bad and takes advantage of its customers."""