Cell C cost me R 5515.77

I opened an account with Cell C (Somerset West branch) in Jan & was given an incorrect contract. This resulted in a complaint (http://hellopeter.com/cell-c/complaints/mistake-of-cell-c-representative-cost-me-r***) which has been resolved (I was reimbursed for Jan expense). After my 2 GB/month is used my acc. goes to per MB billing which I specifically did not want. As soon as I found out about this I went to my branch were they called Cell c cust. serv. & they & I spoke to a rep. that assured me that my limit was now set to R0 (serv. will cut after 2GB). I was reassured that I from now on would not incur any extra cost due to per MB billing. I then received a call from cell C a month or so later informing me that my bill for march had exceeded R4700. I requested that my internet immediately should be cut. I then called the manager at the SW br. who was shocked to discover it was so. Feb bill was R940.93 & Mar bill was R4704.84. So instead of paying R248 (2 month + R50 I requested extra) I paid R5763.77. I was informed that my R0 was reset to unlimited again. Although I have informed Cell C of this matter it seams nothing is being done to reimburse my R5515.77. Pls Help