MTN ACCOUNTS AND BILLINGS USELESS

Good Day I have a mtn contract for more than 7 years and recently i am receiving problems with them i had a debit order that went unpaid debit in May this year but a payment of R1934.03 was debited on 30/06/2015 there after I also send a mail to their customer service stating that as of end of July I will be making cash payments and that they are not to debit from that account any longer I realised that I am experiencing problems with the device I took it to the westgate branch and it was booked in as time went on I heard nothing with regards to my phone only when a woman called me on doing a survey for mtn and I told her the problem with the device the following day I received a call from a woman at the repairs department saying that I am owing them a R 330rand service fee and if they should repair the phone it's gonna cost me another R1600 and some odd I rejected the repairs as the phone is under warranty now that I am trying to sort that out and sending mails to customer care I am being suspended for another R 2500 of which i cannot see what for I have send them proof of my payments and up till today and since morning no one has attended to this matter I never had this.