MTN from the start has no customer service!!

On the 29th September, I was adviced that I was handed over to Vericred for none payment - even though it was mtn fault because the billed me incorrectly from the start, it took month to sort out the credit that was supposed to be passed another months to short out the actual contract payment. Once all of this was sorted out I started making payments. Every time I made a payment whitch included the current month and arears which mtn agreed upon I send the proof of payment to them. With Septembers payment MTN then informed me that I'm handed over to Vericred for collections?! No one from there office has contact me via phone or email!!? I then phone that company and they advice me that I'm in arears for over R14 000,00 which is more than the original contract amount??? Then they proceed to tell me that the last payment they received was on April?? So where is the last 5 months payments I made to this account??? I've contacted mtn daily with no response??