Also report them with Dunn & Bradstreet which is like the credit reporting companies are to individuals.  It will affect their business credit.  We have a WAY overdue from Justice Title and I've posted before that the owner Brad was belligerent and profane to a few of us here in the office - we opted to go the route of a collections company first.  Gave them their cells numbers, emails - everything and we pay on contingency.  For $1500, filing a civil suit out of state could grow costly so we went this direction first.  (I hope their phones are ringing like mine did in college haha).

Whatever you do, don't just accept it as a loss without trying a few things first.