Homechoice order

I ordered comforter set at Home choice, I then received the order but I then realized it was too small for my bed. Requested an exchange, they came to collect and few days later I got the correct size. After a month of paying I received an sms with an amount that we didn't agree on. I called to inquire and I was told they only received one box of the collected set but fixed it. After a month the same problem again, this time around I was told they didn't receive the boxes at all. I am now sitting with a bill of R3600 that I must pay and I cannot afford it as they are charging me for the two orders of which one I returned. They are now threating to handover the matter to the lawyer even after I did what they requested me to do, to write an affidavit. I have been calling them with no help Please help