How one should react

I wonder, when someone thinks you owe them,how do you explain that you don’t.  My mom asked her friend son-in-law to help her out with insurance after her car accident. I didn’t like that idea, but went with it. Long story short, I ended up doing all the work and negotiation, but today, he had anaudacity to ask for money. first of all I told him its not mine do share and my mom will take care of it when she returns. he didn’t like it and start calling me names. I dont have patience for that type of behavior and I hang up the phone. but it still bothers me where he got an idea that we owe him money. I am buggle with that type of behavior.