Unfortunately, I do not believe there is any possible way to get deleted knights back. That is why they are "deleted." If there is a way to get the account back I wouldn't know.
I do feel bad about this though. I have also spent loads of money on getting my own top knight to perfection. The only way to avoid this problem is not go around it in the first place. If you never try to delete a knight this threat doesn't even exist.
If there is someone with more experience with this take their answer instead. This is just my own guess and solution.
I don't think it's recoverable.I'd deleted my double inactived acc with careness without clumy movement.
Sometimes,it's hard to move on because of Accidental Account Deletion..
There might be some people that deleted before might help.