MTN ripping me off beware customers!!!

It is with a heavy heart that I noticed that MTN is overcharging me on my contract.I up-graded my contract to get 40gb data monthly which just vanishes quickly.My question is How is it that when I was given 20gb promotional data for the first month on new cell phone contract,I would not be able to finish that data?Now I have twice the amount of data to cover me day and night it just disappears.Anyway my main problem with them is that I took a contract which would cost me around R200 but for the past 3 or so months they pushed my fees to 300 because my upgrade was a downgrade,meaning I had been paying R350+ approximately in my previous contract, now I took a deal for less when my upgrade was due.I tried calling their customer care but I never got the help I needed.It would be very unlikely for me to recommend this network to anyone.People beware we are being exploited#Frustrated and agitated customer.