False Sales

Hello, I desperately need help please, my problem is with Cell-C, the are not adhering to the contract that we agreed upon, one of their agents called me to purchase some goods, which I did, we discussed the agreement, as it was a telesales, I have required the recordings for the deal that we made with them, they in return promised to send it to me in 48 hours, and will contact me then, then they proceeded in putting the phone down in my ear, since then (jus over a month ago now) I have not heard from them, and they are not taking my calls on the number that was given to me by the Nelspruit branch, but to no avail, it is the end of another month again, and they are debiting 4x the amount that the agreement was, they have also not sent me any documentation , this deal was done in the December 2015, Please advise me what to do?? PLEASE HELP ME?? Estelle