REQUESTED PREPAID PACKAGE, GOT OPEN LINE

We requested a miagration on one of our contracts last year, I explained we work on budget and we DO NOT want an open line. For months we paid our set amount on our contracts, but soon realised in that the migrated line we on average a R1000 more a month, I reported this matter in February, I got a reference number, for almost 8 weeks I have been phoning, I have records of times, dates and person I spoke to, every time we were told that the matter is escalated, but nothing happens. Since Monday I insisted on a senior member to assist me, I was told there are no records of my complaint and that I need to report it again. I find this service poor and unexceptable, I need to pay the account but I will not do so untill this matter has been resolved as I believe there are an amount due to us. every month we are forced to pay more that what we requested otherwise the lines get blocked... WHO CAN ONE TRUST TO GET THIS MATTER RESOLVED?????