You haven't mentioned what specifically is wrong with the amp; and whether its still under warranty. Have you tried mailing the company with a problem description?
Assuming that you have no option but to look for unauthorised repair, I would suggest going to any of the hi-fi dealers in your area (e.g. The Shop), who may point you to a repair service they usually use. If it's a standard topology, then minor problems such as a bad capacitor should be addressable.
If coming to Carter Road is an option, Nova Audio is usually quite cooperative and will help you as a goodwill gesture. I've used them for minor off-warranty repairs and it's been a good experience so far.
Hi, thanks for ur advise this amp i bght it from Australia & it is almost 8 years old. so there is no warranty and problem with amp is one (left) channel is not working at the same time i want to get it serviced also i know this shop in Andheri u mention but his chargs r very high i can try this Nova Aodio at Bandra (carter road)u mention in ur reply can u pls give the xact location of this guy or his contact no.thanks