That's the right thing to do, just move on and learn from your mistake, if you continue to lend money, there's still a possibility that you will have a delinquent borrower, that's part of the risk. I suggest you limit the amount you lend, don't trust so much even if a member is highly trusted, it's still an unsecured loan, you cannot go after a person if he will not pay, all you can do is ruin his account but if the borrower does not value his account anymore, you still loss here.

Maybe allow only borrowers that are hero up, that way, they won't just scam for 0.005 because they know the market value of their account if they are going to sell it. I'm not saying they'll have to, but there's a possibility that they could sell their account at a higher amount.