My Canon Powershot A620 is fixed by the authorized Canon Service Center in Hyderabad. I gave them the camera over the weekend and they called me back on Monday saying that the camera is fixed. That is an impressive turnaround time. The faulty zoom switch is replaced and the camera is working fine now. The cost of component and service is Rs 1200 (about $25). I am really happy with the speed and quality of their service.
For those who are interested, the service center is in Abids. Hotel Jaya International Lane, opposite Reddy Hostel. The name of the shop is Ashoka Timetronics.