Mel, my career was in marketing research and many of the terms you used are part of that vocabulary. However, we hired mystery shoppers as regular employees and gave them a shopping list with a credit card issued by the client. Our employees' personal bank accounts NEVER even entered into the equation.
Please photo copy everything, both sides, including the envelope, with at least three copies. Send the originals to your state's attorney general immediately.
Send a set of copies to the BBB by snail mail.
Send a set to the attorney general of the state from which it was postmarked.
Keep the third set in your files in case you find you'd like to send more copies to the federal prosecutor or any other agency.
It's unAmerican to front money. It's just a scam, but please tell Alan to expect a check from me for $1 million, half of which he can keep if he'll just wire me the other half.