Supposed friend is now billing me for volunteered work

Hi everybody, I am going through a hard time and am looking for some advice. I have what I thought was a good friend, who agreed to help me work on my house and is now turning around and charging me and my family because he thinks we took advantage of him. Basically I work full time and I am doing home renovations. Most of it I can do myself and other projects I just had a few questions for him, but he ended getting up totally involved in. I think because he doesn't trust my work. He can't work because of his health right now yet on occasion he'd message me stating he's bored and wants to come help. Great! In the past I've asked him to work for some odd jobs and paid him as we agreed, and every penny was delivered as promised. He's sending an invoice now because he feels taken advantage of and it's basically billed out for his time, about $1500 worth. I am not sure what to do. My family and friends tell me just to ignore him because it's just adding fuel to the fire. One thing is for sure and that is we are not paying. He verbally agreed to help us out free of charge. He's upset because one day we were working together, about half way done and I told him I had to go. He insisted on staying, saying it's fine it's fine, and then later sends me a long msg saying he feels taken advantage of and that I owe him money. What's worse is that he knows we don't have any money. I've known him for about a dozen years. His passive aggressive behavior is not new to me. I am coming to the conclusion that he isn't a real friend and I am having trouble burning the bridge, and he doesn't seem to want to talk about it in person. On a last note we used to hang out nearly every day until he moved away in winter. When he moved away I met new people and changed my lifestyles a bit. He had to come back in spring because of surgery and he sent me a msg saying how unimpressed he was with me and that he wasn't going to spend time with me anymore. I let it slide and we eventually hung out again...but basically he consistently thinks his time is more valuable then others and I get the feeling that he really doesn't value my friendship. Thanks!

Firstly, if your 'friend' is a qualified trades person, then yes, he's going to think that his time is more valuable because it's how he makes his living whether he's working or not. Secondly, you are correct, he's not your friend at all, rather, he's an acquaintance of a dozen years, because a true friend will help you out whatever the circumstances and a true friend will 'lend' you their expertise to help you get the job done with no questions asked. Of course, you being the person you are, have paid him in the past for his work because you've done the right thing by him. Thirdly, his actions of not wanting to discuss it with you face to face, particularly when he feels he's been taken advantage of, should tell you what sort of a person he really is. A true friend would never let this sort of situation develop nor would they even think of charging you for their friendship. If you feel he doesn't value your friendship, then ask yourself why you need a person who is part of your friendship circle but has no respect for you...it's that simple.