OK folks, the saga continues....
Brief recap:
1) Buyer places order $300 item
2) I Send item and 2 weeks later buyer says didnt get it - tracking says refused
3) I ask him if somebody else refused it in his house - he says no.
4) I spend 3 hours of my time dealing with usps to trace package
5) Buyer leaves me negative feedback
6) Next day buyer calls Amazon CS and tells them his address is wrong in the order.
7) Couple days later the item comes back "return to sender - refused"
8) I spend couple hours phoning and emailing Amazon to remove the negative feedback since it was buyers mistake on the address. After 6 tries finally they remove it.
9) I send item back to his corrected address at my expense
10) Week later I get an email to my personal email from this guy - says he wants to return it as it "isn't working the way my old one used to".
10) Call AZ and ask them how this guy got my personal email - rep says they do not give it out.
11) I send email to buyer thru AZ saying he can return it for repair under the warranty - I send him a prepaid return label.
12) I get unit back today - look at it - it is not the one I shipped out. It is cracked as though he dropped it. In the box is a note that he is returning it for a refund. The note is written like he thinks I have a separate "returned item" depot and I guess he thinks the clerk there will just put through the refund.
So that's the happy recap... BTW - I googled for my address and although the domain naturally is there - the actual email address is not. So probably AZ did give it out. Maybe I will casually ask him.
Yeah... let me do that first before I tell him to go pound sand.
Customer got my personal email address 
