This place ripped me off $650 for nothing.

I rented a lens for my sons first communion and when I went to use it noticed there was a dent in the lens and a plastic cover was missing. I emailed them and told them immediately which they replied that they knew about the dent but not the plastic cover, I didn't even use the lens because it was noisy and in rough shape and wanted to ask for a refund. Now 2 weeks later they decided to charge my creditcard $650 to have the lens fixed. I called them and they were very rude.
I didn't do anything wrong and they completely ripped me off.