Paypal...ebay help please!?

sorry this might be confusing but I mailed an item to Thailand from ebay and he says he never got the item and opened a disputer and on paypal I was negative 64.00 and the money is on temporary hold to because he wanted a refund. Today another ebay buyer sent me $72.00 and the 54.00 was taken from the $72.00 now I am only left with $9.00 on my paypal account. I thought taking the 64.00 is the refund and he got his money back. Now he says he never got a refund. What happened to my $64.0 that was taken from my $72.00? I had a tracking number from the item but I sadly lost it. Can I go to the post office to see where it went?