Makro not returning back my extended warranty money.

I bought a washing machine at Makro Germiston and took extended warranty. The machine did not work after 3months and they collected the machine and I took another one with no extended warranty. I asked them to send that R1000 for warranty to my account because I didn't buy the machine cash. They promised to do that and now is two years asking for my money from them with no avail . What can a customer do when the retail store is *****ing from the customer and you are paying installment every month?