Taking any kind of revenge might look appealing ( Plus if you have SGC/FAC then you are going to lose that, and the respect of your mates for being a bell end) but you have to think that you are running a small local business, are reputation takes a long time to earn, and 10 seconds to lose.
With B2B I've only ever had 2 firms stitch me up, and it wasn't for much. What usually works with slow payers is just being persistent, eventually they pay up, and then you never work for them again.
Most people are happy to pay up front, if not, then use your judgement...
My personal favourite