Unfair price increase and extremely bad service

I signed an MTN contract in February 2015 agreeing to data charges of 0,29c per mb. However, in May MTN had a price increase of 300% without notifying me. Consequently I used additional 2gigs of data and were charged R2011 instead of the contractual agreement of R598. I have complaint on numerous occasions dating back to early June but to no avail. My official complaint lodged was: at time of signing my contract MTN failed to lodged all information to me regarding that I had a right of choice in accepting a fixed contract or budget limit or unlimited budget. At no stage did MTN communicate this to me and I had a right to information. Secondly at no stage did MTN advise me of a price increase. Please I do not despute the DATA usage but merely the price increase. Then worst of all MTN customer care is non existent including trying to contact MTN executive management like Mr Nyati who never ever answer his calls. Not to mention MTN reception who always transfer you to the wrong department and refuse to transfer you to any of MTN executives. It' seems MTN executive like Nyati and its chairman is above its customers and not a bit concern of any of the clients.