These guys are correct. MO's are not guaranteed good funds and are used by individuals in lieu of checks. Even if not counterfeit, the issuer of the MO (i.e. Travelers, WU, etc.) can/will bounce them back if they think they were fruadulently issued. The seller is just protecting himself from being scammed. I agree with the fact that the seller is still communicating with you bodes well that the sale could be legit.