MTN **** to me now they are billing me

I ordered a router and was told that the 1st month will be free and suddenly I am being told that I had to pay the 1st month and my account was in arrears, I did try look past that and now 3rd month I am being told that because there was an issue with me not paying the 1st premium i will have to be charged an amount of R5000. I requested that they come collect it and cancel before from the beginning I was **** to, no one has collected. None of this was part of the agreement.