Three escalating templates — reminder → formal demand → final notice. Fill the details once; every letter updates live. A written demand trail is what wins PayPal G&S disputes and small-claims cases.
DM the reminder on the platform you lent on. Screenshot the sent message — that's Exhibit A of your good faith.
Formal demand goes by email and DM. If you have a mailing address, certified mail with return receipt turns it into court-grade evidence.
Final notice sets a date — keep it. Open the G&S dispute (you have ~180 days) and file small claims. Attach every letter.