Marantz service

I have a Marantz SR7005 receiver. It has had problems from day one. It wouldn't do software updates and often needed to be turned off and back on to recognize sources.
I finally sent it in to George Meyer factory repair center maybe 6-8 months ago, when it came back the Audessy would no longer work and sound out of only one speaker in certain conditions, called them back and the service dept was on vacation I was told. So I sold it on ebay disclosing problems, buyer couldn't get multiple features to work and initiated a dispute and sent it back to me. Now I sent it to another Marantz repair center and am told because I don't have the original receipt they cannot service it. I called the dealer where I bought it, they had a computer crash and don't have records from when I bought it. Hours and hours and hours for an expensive unit that hasn't worked from day one. I think I am just going to tell the repair center to keep it and don't contact me again. Marantz says they can't help me.