Absolutely **** service

I Megan Cloete have been fighting with Mtn for the last 2 years to sort out a mess up they made. I signed a contract for R549 and they decided to charge me R649, which I refused to pay so now that my 2 year contract is up they won't let me upgrade as they refuse to sort this problem out, I have been calling for the last month getting 1 reference number and then another and still no response. I am completely tired of no response, so I will like to warn that other customers must please look at the contract you signed and the amount you paying.