MTN not assisting at all

I downgraded my MTN contract 9 mths ago. I had OVER R6 000 airtime in credit. MTN only wanted to allow R6 000 and I reluctantly took it better than nothing. I chose a package with the commitment that I would get the credit from MTN. This was not entirely the truth. After 3 mths I noticed that the \credit"did not reflect on my statement. I made contact with Nkosi (store mng) whom confirmed the credit was due to me.<br> After Nkosi corresponded with his powers that may be I was informed that the Credit was only valid for 30 DAYS! Problem was that MTN neglected informing me that it was only valid for 30 days before I signed up with them again. Nkosi and I then requested the voice recording to confirm that I was NOT informed of the 30 day period. Nkosi tried to ask MTN for assistance with no joy. Not even any compromise. I had to migrate to a new deal and Nkosi was only able to deduct R300 pm coz I use my own handset. I have been a loyal and excellent paying customer to MTN for over a decade and I used to tease others for not using MTN"