faulty goods

I bought a Sony shake and its fully paid up and still has guarantee, that system is so faulty that it has to always go to repairs even now it went for repairs for the 4 th time, i phoned the head office and even went to the branch that im not using my sound system sunce ive bought it cause it always goes for repairs, the branch manager is always busy when i try to go talk to him so all in all I feel so helpless cause now it sad to spend more than 10000 on something u don't use