That really sucks—sorry this happened. A few things you can try:
Appeal again—sometimes it randomly works on the 5th or 10th try. Use this form.
Contact Meta via Facebook Ads Support—even if you never ran ads. Go to Facebook Business Help, start a chat, and politely explain.
Email these addresses (no promises, but worth a shot):
Post publicly—tweet @Instagram or @Meta with details. Sometimes public pressure helps.
Check if it was a mistake—like a false copyright claim or mass-reporting.
If all else fails, sadly, you might have to start fresh. Backup your content next time (Google Drive, etc.). Hope it works out!