Oh dear.
edd, you buy a new water heater for your house at Lowes and then hire someone to come install it for you. It goes belly up the next week. You now have to go get another one, under warranty from Lowes. You call up the guy you hired to put the old one in. You think he is going to put in the new one for free? No way, no how. He might offer you a discount, if he's a nice guy, but certainly isn't going to work for free when the part was defective, not the install. That's the key issue here, the 3rd party part was defective, not the install.
Jeremy