Brooklyn, why bother with a sincere letter about those things? Does it matter what they write back, they are not going to explain it in any fashion other than the way they have explained it to others.
If you were going to write a sincere letter, ask why them why they are not showing you Christian love? If you aren't df'd, why are they shunning you? If you are df'd, why aren't they treating ones like the Prodigal Son ......... running to embrace you when they see df'd ones come to the hall for the first time?