have you smoked any yet? if not, call him up, tell him you know it's moldy, and you want your money back. tell him you'll bring him the bag and he can weigh it out and see that none of it is missing.

also, be POLITE and CALM when you do this and you'll get a POLITE and CALM reaction out of him.

P.S. i didnt read your above post so my post may not work out... but you still should call him and tell him that it was moldy. ask him how long he had it too, and where he got it from. it's always better to KNOW your dealer's suppliers because they're basically your dealer too.