Mtn overcharging customers on contact.

I had an mtn contact for home bundle data, the router was damaged on February, I called them to let them know and ask that we cancel the contract on which they say I was supposed to be penalized for it.had to pay a thousand and some money for only 2 months that was remaining for the contract to end but the monthly payments agreed on the contract was R270.I tried calling them end of March to check if we can reach on an agreement if I get a one month early contract cancellation,their lines keep kicking me out,thus I could not get hold of them.Now being in May I called them to check how much m owing since my contract should have ended,m told m owing them R1498, to my surprise my contract was R270 per month and the last time I contacted them,end of February my account was up to date, something is not balancing with me on how can a R270 contract be owing R1498 in 3 months.This is weird to me,my hope is lost from MTN as a business that serves the public,my trust is lost in them.