Hello,
Your problem is really unfortunate. Social media sites are often quick to ban, without giving the concerned party a hearing. I understand you want a letter to send to Facebook, to plead your case?
In my experience of dealing with Support teams across various sites, I have found that the best policy is always to be friendly and apologetic, and to not make any demands outright. I'll apply these to your letter (or you can do it yourself, if you change your mind about hiring a writer), and hopefully that'll bring a favourable result. Let me know if I can help.
All the best,
Priya