I wanted to know if you have any essays/ articles on the following topic:
“Contracts in Business law vs. contracts in Halakha”.
I also have the following question: I know that in business law an oral contract (vs. written) is very often valid. Is it so in Halakha as well, or does Halakha/ Beis Din require that it be written?
If a jew told his friend that he’ll pay him $500 for service and no contract was signed- Is there a validity to his words?
Please see the following post, which might be helpful. https://dinonline.org/2019/07/18/monetary-business-law-vs-%d7%93%d7%99%d7%a0%d7%99-%d7%9e%d7%9e%d7%95%d7%a0%d7%95%d7%aa/
Regarding your question, when a person gives his word there are times that it is binding. In regard to a service, it would depend on a number of factors, if the services were rendered, why they were canceled, did the person already start working, and would have to be evaluated on a case by case basis.