dude. contact the bank. they can do something cos u paid by cheque, they also will contact him cos ypu haven't recieved goods. so they should be able to return cheque. either that or call cops as they will make the bank hand over the details to them and they'll pay a visit.
good luck mate.
out of curiosity, any idea which bank he's with, i work for 1 u see, if it's mine i might be able to do something for u.