Unless you can afford/expect not to get it back, any private loan should be treated as a business transaction and have relevant paperwork and payment plan and details of what steps will be taken if payment is not made.
Then you need to adhere to what you have agreed - even if it means going the legal route.
But doing nothing for several years and then wanting to embarrass someone is not a good idea.
If there's no hope of recovery, move on.
Funny, I gave a loan about the same time to someone and she won't pay it back - even after 20 years married