****ed off customer

Last month I took out a contract for a home router with MTN at one of their shops in La Lucia Durban, contract subscription was suppose to be R399 for a 120 gig package. Imagine my shock this morning after discovering they have debited R1260. When I call their customer care to enquire they told me their records show my subscribtion is R800. At no point during the contract process was this communicated to me and I wouldnt have agreed to it as I cannot afford it. Their call centre said they cant assist me. I have requested for the statements but I have not received it and I cannot believe how that consultant ****med me. Theres no way I will be paying for something I did not agree on. MTN better sort this out or I'm taking it further