Absolutely no Service

I had a contract with MTN and wanted to 'upgrade' to a cheaper contract. After visiting a local MTN shop (with a lot of hassles with inexperienced ever-changing staff) my number went over to 'Pay-Per-Second' billing with me having to buy airtime. I wrote several -emails to MTN Customer Service and up till today did not have a reply/response from them. After visiting another MTN shop I was told that I still owe MTN money and if I pay the amount of R500.67 I may upgrade .... I NEVER received a statement or any correspondence from them. Also, my contract was for the amount of R350 per month and I have no idea where the amount of R500.67 comes from. Apparently my account is at their Legal Department. I will have no option to see if the ombudsman can help me so I can keep my number and change over to another service provider since MTN's 'Customer Service' are simply not interested in their customers. Just for record purposes: I've been an MTN client ever since cellphones started, never had a problem with my account or billing and is extremely sad that their service deteriorated to an 'absolutely no service'. I will appreciate it if hellopeter can assist with my account? (I will provide my account number to you)