Why do you ask a buyer to send the defective or damaged product back to you? Why do electronic companies spend huge amounts of money on service centers?
You should always advice the buyer to take the product to his nearest service center. On you part you should give him an invoice which he needs to product at the service center. You must also fill up the warranty card and send it to the buyer.
Service centers and call centers have been set up by almost every companies because they know that at some point buyers will end up complaining about something. So there should be someone to take care of all these stuff.
I do not sell electronics. However, when I do I will search the buyer's nearest service center and help him locate it.
If you ask the buyer to send the item back to you and again send a new one to him, that means more courier charges. No one is happy to pay the extra shipping. We need to change the way we handle buyers requests.