TS, if you have black & white proof that you sent in for RMA before warranty expired, go to consumer courts. They have to either give you back same model OR higher model but you top up to make for the price difference.

The point about the card is out of warranty when they refer back to Sapphire is NOT customer's problem. Whomever handling warranty at their end should be aware of the warranty status of each items customer sent in and keep track of it. 

You have your rights as a customer, TS. Try approaching Consumer Court and ask for their advise. See what they recommend.