That's hard luck John...There are some real tos***s about. Just take whatever lesson there is to be learned from this and move on....but don't forget!
Up to my recent retirement, I had my own business for some 45 odd years and been bitten a few times. I've passed on my experiences to my son.....Never trust anybody, bit harsh but it works...usually.
I write 'Usually' because he was a victim recently. He went to a customer's for payment for a job and the customer insisted he pay in cash....When this happens, I always say to my son..."Count it in front of them."
He forgot and stopped down the road and counted it....it was quite a sum short. He went straight back and said it was not enough.....The customer denied it was so and told my son to leave......Tough, you may well think, but the customer was a very, very close family member......someone, of all people, you would have though trustworthy.
John, the vast majority of people are 100% honourable, but it takes just one wrong'un to upset the cart and it really hurts......
Oh yes, all payments cash or otherwise go into the bank and are accounted for...another golden rule of mine!