OP,

Just sit tight and don't have any more contact with the angry man or ex-wife.

This is a $225 pinball machine we're talking about, not the Hope diamond.

If anyone important ever asks you why you didn't simply return the machine, you have several legitimate answers to give:

1. No refund was offered.

2. The angry guy never proved that the machine was actually his.

3. You already started the restoration of the game and did not want to give up the time and money put into the game.

Note that sometimes people will make up a fake letter from an attorney and send it to you in an effort to scare you into backing down.

I'm guessing that the angry guy did not really give a crap about the machine and probably just left it at the wife's house out of convenience.

Now he's mad that it was sold because he has the usual delusion that it's worth $2250 instead of $225.