Reading all the posts here... This is exactly why lawyers remain in business, despite the power of the internet.
Feel free to TL/DR everything up until this post:
$10-$20 K loan 10 years ago.
1 - You're in small claims court territory;
2 - It was TEN years ago.
There's only a rudimentary outline of the circumstances you have provided, but:
First, it will cost you ~$500-750 to get up and running. You'll have to prepare a claim; serve it; file it. Sure, you can prep it yourself, but then you're stuck with it so don't make any mistakes (there's a reason why in a simple fender bender, lawyers initially claim everything under the sun [and, beyond the sun] as the fault of either party). Then, your affidavits to go with it all.
Further, you're statute barred from making your claim. The 'Statute of Limitations' is two years... And you're at ten. So, you'll end up with, at best, a judge saying, "Yup, he owes you some money, but he actually doesn't owe you anymore."
Don't believe me?
Keyboard lawyers, rejoice, I come with examples.
See, for example: 2016 ONCA 559.
But, wait, you think your situation is different than all others covered by the limitation period and you're someone special?
Are you more special than an entire Indigenous Nation? As they, at best, got "Declaratory Relief" (see above about "He was bad, but, you're late."
See: Shot Both Sides v Canada, 2024 SCC 12.
To quote Ellis in No Country for Old Men:
"All the time you spend trying to get back what's been took from ya, more's going out the door. After a while, you just have to try to get a tourniquet on it."
End of the day though? Spend ~$500 to go to a lawyer and get a 2 hour consult (1 hour of them to review an outline and a "brief" series of relevant documents, and another hour to walk you through it all). Don't spend good money chasing bad money. Hell, this is an escort forum, if you want to throw a few thousand away, let alone waste countless hours, just leave The Lounge and move down to the Escort & Massage advertiser threads - at least that way you'll have a smile on your face after spending a load of money, rather than your lawyer/paralegal/etc. when they cash your retainer cheque and monthly top ups.