An angry client

I bought a plasma tv from ok furniture in seshego circle centre after a couple of months the tv was not showing any picture, i took it back as it was still under warranty they fixed it and brought it back then it worked for a couple of months and crushed again i took it back this time they wrote it off and said i must choose another one the one i chose was priced R2500 more than the initial one so i had to pay that amount to get the new one the same day i collected the new one from the store when i got home it had problems, the store now says they wont be responsible because it left the store its no longer their responsibility, my argument is even the first one i bought was tested at the store before i took it but it gave me problems after that and it was factory fault, so now they want me to pay additional R4000 for fixing the new tv. I am very disappointed with the way they handled this whole situation.