Lenskart - Product got rusted and lenskart not helping

I tried to talk to customer service several times and went to the store as well, the frame I purchased got rusted which they claimed while selling that it won't get rusted. now it's been * weeks post warranty period and the frames (screw) got rusted and the hinges which hold the lens in place broke. now the store manager told that this is completely sue to the rust and the frame is in the great condition, no wear and tear on the frames. the customer service won't help with this even after the store manager raised the requests for replacement. they think of a customer as a fool and keep quoting policies and guidelines.