rebooking and billing

Am sorry to hear that you still giving me the option of rebooking the item which I was given long time last year to solve the problem of which I did and never helped coz it came back as it is I don't know what you really want me to do because its already 2 years now and I even qualify for upgrade and on top of that I didn't get my montthly credit and I tried calling you call centre but no answer even the self help isn't working till today I went to menlyn and they sent an email promising to cc me feedback but nothing on top of that I was even over billed to the amount of close to R3000 which I never utilized on any airtime or megabytes. I am now confused and in the dark of what is happening to mtn company.