Hyundai Motor India — Incompetence of service station

Address:

Aurangabad, Bihar, 824101

There is an unusual banging noise originating out of front fork area in my elite i20 car. I visited brij hyundai service station (Gaya, bihar) but those guys could not troubleshoot the problem and they did not pay much attention about it. I even sent a mail to hyundai motors india ltd but they did not respond. My car is still under warranty, what to do