[Resolved]  Videocon 29 Inch TV Model No - CTVis294 — BUZZING SOUND AFTER USING THE TV.

My videocon 29 inch tv when v had brought in 2006 it worked just fine .It developed a problem in 2008 july, which was a kind of buzzing sound. this sound was initially less but then this sound graduaaly increased now its very irritating there is echo of the voices also. we cant hear the dialogues etc clearly.
my tv is under extended warrentyso i called for the service man who said he will get the damaged part replaced from the company and had come 13 days back with the part. but while fitting the part he noticed another problem with some other part after which the tv is not starting only. i have been calling this idiotic service man who switches off his phone once i call or if he picks up he says it will be repaired just then he is on his way to my house, but never turns up.
please help me.