So, I've recently started trying to run a business on the side setting up sound reinforcement equipment for DJs and stuff like that. This is a kind of new area of business for me, and I've recently run into some issues with a client. Given the nature of the work, these issues may come up again and again so I thought I'd ask here.
This client was actually a friend of the family, so I gave a discount on my usual rate. This guy didn't know what he was doing with his gear at all, and I spent a great deal of time working with what he had to make it sound the best it could.
I provided him with an invoice for the work with a due date, and the date has now passed. Apparently, the client's father-in-law looked at the system and decided he didn't like how I had set it up, even though it was a thousand times better than how it was before. He thought the microphone sounded "tinny" (not a piece of equipment I provided) and that the feedback destroyer setup wasn't completely killing feedback frequencies to his liking. Told his son-in-law not to pay me for the work.
Son-in-law is now digging in his heels, saying I have to spend a lot more time getting it "just right" before he will be allowed to pay. This is a completely open-ended situation and it may never be resolved, and I have a bunch of money in equipment and cables sunk into the contract that I may never see because I just don't have any more time to work on it. At this point, because I don't want to alienate my friend, I may just have to take a loss.
How to avoid this in the future?