Wrong information by agent leads to huge bill.

On 22 September I contacted Telkom for the 2nd time in order to change my prepaid fixed line to an ADSL line. As with the previous call (and one after that), I wanted to confirm billing on this issue. I was told by THREE agents (one named Melissa), that my rental for an ADSL line at 2mbps would be R189. I double-checked each time to make sure that this price was all-inclusive, i.e. line rental and ADSL. I understood that phone calls would of course be separate. My first bill, paid 23 Oct, was for R323, which I assumed was pro-rata and the next full month. On 17 Nov I received a bill for R1855,55. Service fee for installation (none needed - existing line) R694, and Transfer fees R481 (I was informed that no fees are charged to change the nature of the line). The lovely call centre informed me that I have to pay, then log a dispute and I MIGHT get my money back, as I must have misunderstood!!! I REFUSE TO PAY THIS MONEY as I feel Telkom either mislead me or made a mistake with my bill. I even told the agent to check phone recordings to confirm my side, but she said it can't be done. Please, anyone, assist. Who has that much money laying around?!