A few points to bring to the table.  Does anyone know if his business is structered as a corporation or is he just a dba?  How his business is structured will make a difference in all of this.  Let's assume Matt has a legit business as in paying business taxes as Matt Hatfield Racing and is also set up as a corporation. He is going thru a divorce and she will most likley give the judge a story about how she was a big part of the business and helped build it blah, blah, blah.  Then she will either want part ownership or for Matt to buy her half of the business.  It's possible he is running the business into the ground to  either lessen the value of the business or he plans on making a train wreck of it then handing it over to her and laugh as he walks away.  Going on the assumption above that he has a structered corporation you will be taking Matt Hatfield Racing to court, not Matt.  As far as the law is concinered you made a deal with Matt who represents Matt Hatfield Racing.  As crappy as it is all he has to do is file bankrupt and any judgements against him are put on hold, the companies assets, if any are sold and the judge decides who gets how much if anything for the selling of the business assets.  It would be possible then to take Matt himself to civil court but depending on how his business was structured it would prob be a fruitless effort.  This is all assuming his business is structured as a llc.  Been thru something similar in the past as have a few friends.  I lost close to 5k in the deal.   I hope everybody in this deal comes out ok in the end.

Pretty sure you can't be a dba if you operate out of a shop and keep merchandise there.