Failure to rectify account and contract

Dear MTN <br> <br> On the 2nd of May 2015 I received my upgrade from the store in hartbee****rt. From the moment I turned my phone on I have either not been able to use it, load airtime or, like now, you want to take R4330 from me, when my contract states that I should only pay R425 per month. I have called amd sent emails and the store has sent quieries and emails the works. YOU STILL HAVE NOT FIXED IT!! 120 days later, a Full THIRD of the year to fix it still has not been done!! I do not have a credit limit and neither do I want one, I only owe R425 for 4 months .How hard can it be to solve something that you work with every day? <br> I expect this resolved immediately!! You have had enough time to fix it and I am not paying anything more than the R425 a month on my contract ,you didn't create the correct contract , that is YOUR PROBLEM!!<br> FIX this or I will do what I have to in order to go to another network . <br> What an absolute ******* and waste of time.<br> The Hartbee****rt store staff however are brilliant, knowledgeable and helpful.