Small claims court?
If they owe you less than $500 I would walk away.
Unless you can get on Peoples Court and have your designs shown on television.
I am still out over $2000 from a job I completed, it would cost me more in time, effort, and legal fees to ever get the money, so I just moved on.
Get your money up front and when they request changes tell them how much more that will cost and when you receive the money do the work.
Sometimes you become so familiar with a person you forget what they are capable of.