We work in a business frequently done by handshake. It is with many older people and we have had a working relationship that has lasted many years. The father of a family owned business that is one of our vendors died. His sleazebag son took over. He is now trying to get out of our contract claiming that the deal to buy a supply of automotive parts regularly this year isn't legally sufficient. He says it is oral, no written contract. Everyone knows this is bull bleep. Any thoughts and recommendations?