Never heard of ABF, but it doesn't matter -- it's a scam. FYI, a lot of these scams "borrow" the names of legitimate companies.
I collected these instructions for a friend last year:
SHOPPER ALERT- COUNTERFEIT CHECK SCAM -
1. If you receive such a counterfeit check and "mystery shopping offer," you may want to contact your local (non-emergency) number for the police, just to make sure they know the scam is taking place...understand, though, they don't have the resources to go after the scammers.
2. Report the check to the FTC toll free hotline: 877-FTC-HELP (877-382-4357)
3. Report the check to the FTC via its online form at [ftccomplaintassistant.gov]
4. File a complaint about the scam with the Internet Fraud Complaint Center (http://www.ic3.gov)
There may be other resources as well -- I think I've come across them in the past, but I don't have them on hand.