Your still assuming it was sent at all . Have you contacted Ebay about his . You say cancelled , does that mean that someone backed out on a $350.00 MiniMoog ? That's a bad sign right there . I keep finding out more as this goes on . I submit that it was not sent , there is no proof that it was . You say that you are out $350.00 , does that mean that the person who cashed the money order will not refund it ? Do they even respond to you're emails ?

The main problem is
no proof it was even sent
$350.00 for a Minimoog , that does not happen
You can't even get a Micromoog for that much
Someone else cancells on a $350.00 Minimoog , Why ?

I suggest that you try to get you're money back . The whole thing of not having a tracking number is bull . The tracking number when scanned tells where it's from and where it's going . Especially when dealing with customs .
I think this person lied to you .