Home choice refund

Was a customer at home choice for a very long time payed off all my accounts and about a month after completing my accounts home choice gives me a call asking If I wnt to buy something again..i sayed NO..they sayed that if anytime I wnt to buy I can cause I have R925 available credit..i still sayed no 3 days after that call got a call from home choice again..and this time I also sayed I don't want to buy..but something els happened..the lady sayed that I can get a refund if I don't want to buy..so I sayed yes please and 3 days later the R925 was in my account. Now the problem.. Home choice calls me a month later saying they need my installment I sayed but I'm finished wit all my installments Home choice says no you bought stuff for R925 I told them no that was a refund..they never excepted that..so I sent them proof, the very statement from them that they sent me stateting that the R925 was a refund..they don't wnt to except it like that..they have given me over to collections lawyers..for whom I also sent the statement as prof it was I refund..but they just don't want to except it as that but now my name is under bad payer and is flagged red so can't now open any accounts