POOR SERVICE AND FALSE ADVERTISING

I have been trying to get through to 808 for 3 days now. previously it took me 2 days to get assistance regarding an sms I received from Mtn saying that I was awarded 1 gig data free but I never received it. I then called in and the lady I spoke to said she would escalate the query as a lot of people have called in about the same query and that she would sms me my ref number. Well it is almost 2 weeks later and still no ref number was sent to me and no free gig data but I did get an sms to say that as from the 1 May, my instalment was going up in price. How can you take out a contract for 24 months for the amount advertised only to be told later on that the amount will be increased? The sales representative should then tell you that this could be a possibility before you take out the contract. Mtn service is appalling. I wish I could just cancel my contract. I should have stuck with Vodacom!!!!!