Not good advice Wayne - there is always someone bigger and badder round the corner. If he does that he could end up getting knifed, or even having his family targeted. It doesn't matter how hard you think you are, numbers or weapons can make that irrelevant.
Whats the first thing you'd be inclined to do if you got a hiding? You go after the guy that did it. If he gives you a real bad beating, you probably pay someone else to do a proper job right? These things get out of hand, its not worth starting.
No point in taking a minor dispute to a higher level. Make your customers aware of the situation, and go from there.