What must one do to get any service and results. Involve lawyers????!!!!

I wanted to cancel my data contract the end of Feb when my 2year contract ended as i wanted to take rain over from my nephew. The consultant that day gave me a good package due to being a long and loyal vodacom customer and it was time they give something back for the many years of being a customer. But unfortunately i only got troubles. When i received my invoice early in march i saw that i was billed wrong for the data package on my one data contract. I immediately got into contact with vodacom and was transferred to elite mobile where i spoke to Nhlanla who told me he would log a request for them to listen to the recording of the day i basically upgraded my data contract and was told they'll get back to me within 7 working days. Nothing!! I then phone again and spoke to Brevan whom asked me if it would be ok if he take it upon himself to sort my query which will take 3-4working days which i accepted thinking something will get done but..... Nothing!!! Then after 4 days i phoned yet again and spoke to Andy who promised that they are busy with investigating and listening to the recording and I'll hear from them very soon and again.... Nothing!!!! Then after the easter weekend we phoned yet again and i spoke to Mandla who also said he will log in a request for them to listen to the recording and he apparently marked it as urgent and it will take 24-48hours and they will get back to me and...... Nothing!!!!!!! Then we phoned yet again and i ended up speaking to Mandla again and he asked me to hold he will get into contact with head office and talk to then to get my query seen to. He came back and said head office will get back to me before the close of day on friday 9 April and he will get back to me by 2o'clock to find out if i have heard from head office and guest what...... Nothing!!!!!! I phoned again today 12 April requesting to speak to Mandla of which I've been told he has been send a request to get back to me. Its now nearly 3hours later and stll nothing. What must one do to get anyone to actually do what they say they'll do and in the time they said it will be done. How difficult can it be to listen to a recording and come back to a client and sort out a query. The day i took out the contract i ask the consultant if what he is giving me is what i am going to pay and that there are no other additional add ons of some sort and he guarantee that R279 is what i will pay for 100.5 gigs and now i am being billed R217 for the 100gigs and R227 for the 5gigs like really!!!!! Why would i accept that if rain would have been much cheaper. Does one have to involve a lawyer before anything will get done as i am really at the point to take this issue further as this is ***** and vodacom is *****ling ones money. I would really appreciate if there is someone out there you would be so kind as to do their job properly and sort out the query!!!!!!