http://www.mopicairsoft.ca/Shipping___Payment_Info.html
If that hasn't worked for you I'd suggest contacting your bank.
I've had all my emails and PM's answered by mopic in a reasonable manner on the items I've ordered and received. I'm satisfied with the service I've had from him and would buy again.
Whenever I do see a bad reveiw for a retailer the first thing I usually do is check the other posts of the person lodging the complaint. We have a few folks on here that are well know for launching bullshit crusades.