Replying to WTF Brokerage C.O.D??

Okay so i just traded my EG2s to a dude in the US for his I/Os.  he had a ton of feedback saying he was 100% legit and our transaction went super smooth.  I shipped Canada post (equivalent to USPS).  I paid 7$ to ship and that was that.  I live in Ontario, he lives in Washington state.  we didnt really say how we were shipping, our deal was we would each pay for our own respective shipping fees and trade goggles.

I also shipped three days before him and both of us got each others package in a matter of 1 week.

i got the package today and to my surprise he shipped UPS and now i have to pay a brokerage C.O.D fee of 46.50$.  i asked them to come back later cause i was pretty confused.  I never agreed to have to pay this large fee just to trade a pair of goggles.  whats up?