Can confirm. You don't need a lawyer just to write an official sounding letter. Patio11 (Patrick Mackenzie?) has a blog post somewhere about how to write one. In short, avoid emotional or threatening language, write like it's nothing personal, use words like "require" rather than "demand", set a deadline for a reply, and don't say what happens if it's not met. That should scare anybody who reads it into sending it up the chain. Regardless of that, your audience is not just the recipient but the judge to whom you'll show the letter to prove you did everything you could to resolve the matter before going to court.

I used this technique to good effect in what would have been a clear case of tortious interference because of someone posting false and misleading information about a business. IANAL but I'm not convinced facebook has done anything illegal to the OP.