Sad customer

I have 1GB deal contract for R369 p/m at Telkom, the first two months they didn't deducted any cent from my account. On the third month they deducted R1606.97 instead of R1107, I went to the bank and reverse that money. I went to the store and ask them and they said every month they give me R500 that I can use it for data or calls. I ask them to give me their customers service number and when I call them they said I shouldn't have used it so I must pay it and the said part of this is that I wasn't aware of that R500. They send me statement with outstanding balance of R2678.65 and when I ask they said is for November charges plus penalty fee for reversing money. Please when you open Telkom contract be aware of such thing, they are taking our money in a bad way, (scarm) now I can't pay that money, I have to suffer for many months to pay back the money. Please stop this to save our society.