You did say it was 'a rather large check'.
I am not aware that a 'real' cashier's check can be issued a 'stop payment' unless the originator perhaps claimed it was lost or stolen. The cashier's check was purchased with real money at one time. It's not like he was making monthly installments toward the purchase of the cashier's check.
I thought only the originator of the cashier's check could change his mind (assuming he still has the check in his possession), or report the check lost or stolen in order to obtain a refund.
It may be just a fluke, but I wouldn't chance it. I always hope for the best but plan for the worst. As the motto goes.
So planning for the worst:
For all you know, he may have claimed you stole the check and tried to cash it and now the police are coming after you. I doubt this to be true but people can be really squirrely and clever at the same time and you never see it coming until it's too late.
I would immediately start corresponding with the buyer thru email via audiogon's email system so you and audiogon can begin to establish some hard evidence (email is substantiated in a court of law -just ask Microsoft and Enron). Use email always. (Using audiogon email also makes for a great backup should you lose your hard drive.) Follow up with phone calls if you like but if it must be one or the other choose email.
You could tell him that you are nervous and you are giving him 12 hours to wire the funds to you. (do not give him your banking account info) but to use Western Union, etc..
Ask him for his bank's name, branch, phone number, etc. to see what you can find.
If things start looking fishy or counterfeit, you may want to start contacting his local police department, FBI, Atty General's office of his state, Audiogon.com, etc.. And if you're serious about contacting these departments, let him know what you are doing and what you are going to do. He may cry uncle or at the very least, he'll know he better put his running shoes on now.
If things are looking sour, then inquire with those departments about other departments you should also be contacting.
And if it's counterfeit, forgery, or fraud, the buyer could be in some serious trouble with the law(jail time wise), but you need to move fast because if the buyer turns out to be a bad dude, he's not going to be sitting on his thumbs waiting for you.
Obviously, if the check was only for $100 or so, it's only worth so much of your time to pursue.
It's probably nothing, but start gathering evidence now just in case.
-IMO
p.s. I am aware of an aquaintence here on audiogon who last summer made an exchage with the buyer in person in Southern California. He gave him the speakers and the buyer gave him a cashier's check for around $2300. The seller later went to cash the check and it was counterfeit.
So they are out there.
