small claims court is a simple way of getting your money back, takes 30 mins online at the most. I've just taken another local football club through the courts for non payment of work. One invoice at over 90 days, two more over 60 days. Got paid the day they got their summons. Cost £35.00.
I was booked by SWFC a few years back to do some photography of boxes and restaurants on a match day. Half day rate of £250. On the day before the match I was told not needed, someone in the office will bring their camera in, they thought I'd do it for two tickets on the kop, £40 for half day of work.
So small businesses need to be strong and say f**k it, and take them to court