Eyemyeye Private Limited - Return Refund not approved by misleading through unclear Terms and Conditions

I placed an order of * eyeglasses from eyemyeye.com on **/**/**** and on the products listed it was clearly mentioned they can be returned in * days. Also there was an offer of ***% cash back if we answer some question . But in the TnC of the offer it was mentioned that " Once claimed, you cannot return, cancel, or exchange your order."Now I didn't receive any cash back from them because the question was some GK question which has to be answered in ** seconds. Later in evening when my father checked quality of frame it was found to be low quality. So I wished to return the product but company says since you tried to claim cash back you can't return . Now my points is neither this condition was mentioned in the TnC clearly , nor it was mentioned that you would get only ** seconds to answer or that you would be asked a GK question. I felt cheated . They should have mentioned these conditions clearly and also that even if you don't receive cash aback you can't return. I tried talking with customer care through emails and calls but they refused to return . On twitter when I searched there are numerous people being cheated in same manner.