Incorrect billing

I have upgraded my new contract to my choice 100 in March. I am supposed to be receiving 300 MB, 200 SMS'S and 100 anytime minutes. Since my upgrade I have not received the correct data package - I have only received my minutes and 25 SMS's. I have lodged a complaint at the store and have sent emails to DIC. I have been to the store multiple times out of frustration. DIC has informed me to obtain my contract details and forward it to them. The store has since not received my contract and keeps me on hold with a different excuse every time. While I am paying for a service I'm clearly not receiving and which I did not sign for, my billing statement doesn't agree with what I signed for. I am not willing to pay for anything other than which I signed for. MTN's service has gone down the drain regardless of the continuous strike and as a loyal customer I still need to gain proper service despite that. It's been months now, something has to be done soon.