HisensePlasma Faulty

Hello Peter I thought let me right again because it's seems I don't get a answer.I buy a plasma by ok Funiture for a year and a month now the volume did want to play so I sent it back nd I got it,it was right but in 3weeks it just go off when I took it back they demand R150 by me to open the plasma, and I told them my plasma is on guarantee.Than they say again they don't have parts to fix my plasma,and again that my plasma is damage of ****roache plz can Yu help deal with ok Funiture bec I still have guarantee but they say I must take my plasma. Thx Hellopeter