quest mast3r stole my 90 day pin

I was trying to work out a deal with quest mast3r about his level 107 for sale. He was accepting membership pins, so I went out and bought 2 90 day ones.
He sent me a PM telling me to go on MSN when I got the cards. Now his vouchers say he is a trustworthy guy, and I do know another person I tried to trade with claims they were not on MSN at the time.....I have two chat logs, I can post the most recent one now, and the older one later.

[email protected] (E-mail Address Not Verified) says:
hi
i have both 90 day cards
Tyler says:
kewl
[email protected] (E-mail Address Not Verified) says:
so you want to do the trade?
Tyler says:
def

[email protected] (E-mail Address Not Verified) says:
awesome. let me scratch the codes
Tyler says:
kk
[email protected] (E-mail Address Not Verified) says:
remember, this is two 90 day codes
Tyler says:
so where would section be?
[email protected] (E-mail Address Not Verified) says:
?
Tyler says:
from country?
[email protected] (E-mail Address Not Verified) says:
its from US
Tyler says:
what kind of card?
[email protected] (E-mail Address Not Verified) says:
its a runescape 90 day time card
Tyler says:
walle? pre-paid?
ok
[email protected] (E-mail Address Not Verified) says:
it says fastcard....?
Tyler says:
fastcard?
[email protected] (E-mail Address Not Verified) says:
well its worth 90 days of runescape membership
Tyler says:
k im ready for it?
[email protected] (E-mail Address Not Verified) says:
first one: xxx xxx xxxx
Tyler says:
wtf it says wrong?
wait lemme take spaces off
lmao
[email protected] (E-mail Address Not Verified) says:
that work??
for payment method, you put runescape card i believe
Tyler says:
lol i put walle
[email protected] (E-mail Address Not Verified) says:
this is a legit prepaid card from RS
Tyler says:
k runescape card?
[email protected] (E-mail Address Not Verified) says:
yeah. did it work?
?
[email protected] (E-mail Address Not Verified) said (11:04 PM):
>: (

What can be done about this? I've noticed MSN hijacking has been pretty popular here, so I don't know whether or not to blame him or a hacker....