ZERO AFTER SALES ,PRODUCTS DEFECTIVE THAT THEY SEL

I had a pioneer deck installed , from day one had issues with it ,thought it was my cd format , kept it , after a few months realized that the fault lies in the deck , even an original cd would skip in that same song a thousand times , I took it back to the the fords burg store , spoke to navi who originally sold me the deck , said it would take a few days to get repaired and said no one has ever brought that deck back , its going on three weeks now , no deck , he promised to switch the deck with a sony , which i agreed to , now he is backtracking , on what he promised , i am extremely disappointed , I have been over 6 times to the store and have spoken to staff who have all now confirmed that there is a problem with the pioneer decks and now navi has also confirmed that , is it too much to just replace it with it another brand ,i also agreed to pay a difference of R200 for the other deck yet he insists on installing a defective product in my car , i have taken all my cars to them and will not in the future !!!