Here's how this would go down if it was me:
1. Find dudes home address and a day he will be there.
2. Knock on the door.
3. Look him in the eye and *IF AND ONLY IF NO ONE ELSE IS THERE TO CORROBORATE WHAT YOU SAY* make a serious threat of violence against him. Make it clear to him that court does not interest you and that if your money isn't received he will pay you in pain.
4. Never repeat this threat to him or to anyone else again, either follow through with it ALONE or do not.
50/50 chance you get your money.
If it's me and I don't get paid, I'm kneecapping the guy when he gets home from work some night. Wait near his house, when he arrives go full ski mask and take some rebar to those legs.
It won't pay you, but he won't be fucking anyone else again.
Worth mentioning that the weapon employed should be ditched somewhere safe within 5 minutes of the encounter and anything that might potentially have DNA on it should be burned immediately--shoes included. Never handle whatever weapon you plan to use with ungloved hands, ever.
I realize that's eerily specific and probably sort of evil and creepy sounding, but where I come from if you rob someone you EXPECT to die. Walking funny for the rest of your life is a blessing by comparison.