Hyundai Motor India — Stopped functioning of car air conditioner

I gave my car hyundai verna 2008 model for repair of clutch plate at roshan hyundai vki jaipur, rajasthan where i have been giving my car for last one year. When i handed over my car a/c was functioning but when i got my car back after the repair i mean after six days the ac is not functioning at all and the authority concerned is not ready to accept their fault. They say it was not functioning from before and are trying to blame me that i am lying. I am a child specialist and have given my car earlier as well for repair at same place for repair but never complained though the time taken was always more than expected.