Not being given what I was promised.

This morning I called Vertex and I spoke to Potia and she advised me of my balances mainly R16 229.40 and R6 511.76. I requested for a stellement balance on the above amounts and she advised on the R16 229.40 I'm allowed a 20% discount and on the R6 511.76 I'm allowed a 25 - 40% discount. I just got my settlement amounts and to my surprise they are more than the amounts quoted to me. I called again on the numbers on the letter and no one is anwering and I'm really uncertain of what to do as i feel that this is plain **************** and I'm not happy at all with this service.