Ugh! I don’t mind lending people money but asking for it back is a pain in the butt!

I finally got the courage up to ask the people in question for the money they owe me and already they are disputing it. I know what they owe me, I’ve got record and recepits for it but I’m already getting stressed as I know its not going to be easy getting it back and its quite alot of money. I hate money.