Sunglasses hut and Emporio Armani

My husband bought two pairs of sunglasses at sunglass hut the second pair which was from Brand Emporio Armani suppose to be a quality pair of sunnies is defective. I have been to the Canal walk Edgar's store multiple times to have it straightened, which the consultant has been helpful however why do I have to drive up and down to repair sunglasses.I asked for an exchange I was advised I was out of the 30day period . I was then offer a R 600for the sunglasses that are valued at R2250??makes no sense at all . Why would sunglasses hut sell sunglasses that are valid at R2250 ? And only offer a 20% rebate .Technically you are selling poor quality goods to people if you are only willing to give me back R600 I'm not happy and I would like the value my husband paid for the sunglasses