JDG Financial Services / JD Group review: product guarantee

Hi I bought a Jvc Monster system December 2016 for R9500. The product had a technical error after couple of months and I returned it for repairs. The Jvc group advised me to go to the store for them to replace the unit but the store does not have stock of the unit. I was offered a LG system which cost R7500 which means I will loose R2000 as I paid R9500 initially. I was advise that I cannot take an additional product to cover the credit due to me so at the end off day im loosing