Not sticking to the agreement

I bought a couch on account last year around October at Coricraft, I spoke to the consultant about this specific couch and to buy it on account it would cost me +-R649 per month over 24 months. The debit order starts going off at over R1000 and at one month it was R2000 that went off my account. I go in store to find out what is going on and they phone RCS to see why this is happening RCS says I am not on a 24 month contract but in store when I bought the couch I bought over 24 months other wise wouldn't have bought the couch. its been 3 months of trying to sort this mess out and still no luck, I have must have had about 7 phone calls with RCS regarding the issue and I have to explain myself over and over, RCS tells me to go in store to fix the problem so I go and the store phones RCS and so the circle begins again and again. Last week I get a phone call from RCS and there story has change saying there is hidden costs and interest involved that's why it is over a R1000 etc

They just don't care to help at all in this regard they just want their money and not interested in helping but I am just and individual and against two corporates so they can do what they like... I would rather just give the couch back and I never step foot in a Cori craft store again and avoid dealing with businesses that are involved with RCS.