Vestel TV Freezes and Restarts Constantly Despite Service Visit and Fix Attempt

I bought a TV from Vestel, but from the beginning it has been only trouble. Watching causes a continuous freezing problem whereby the screen gets frozen, then switches off and on once more. This is not a one-time error; it continues to occur and each time I have to wait sometime before I can start viewing again. I contacted customer service, who dispatched someone to verify the cables and informed me they had corrected it; nonetheless, the same problem persists. With this purchase, I feel I made a bad decision as Vestel is not providing the desired quality. I really wish I had gone with another brand; this TV has been a true hassle.