Do this now
- Screenshot the profile with the date.
- Try the name in Settings, under your account information, every few weeks.
- If it uses your registered mark, file X's trademark report.
- If it poses as you, report it for impersonation.
- Use a close variation for now.
What to write
No message is needed. If you contact the holder, keep it polite and do not offer money.
Deadlines to know
- X does not publish a date when inactive names become free.
What to avoid
- Buying the name. X's rules do not allow selling usernames.