Consumer Redressal

I had got my ceiling fan repaired from Orient Electric\'s authorized service center in Bhowanipore in Kolkata. The service center people checked the coil and told me it is burnt and needs to be replaced. They replaced it and charged me for that. I paid a total of INR 682 towards repairing including service charge and other body parts. Later I got that coil(which the service center told was not working) checked from my local electrician and found that it was working perfectly fine. Then why did the authorized service center charge me?