I'm assuming a bit here but I think what he's saying by "can't patch" is that a character whose already been deleted will obviously stay gone even if you patch the bug that deleted them, so he's offering to manually replace those characters.Yeah... I know...
"This cannot be fixed with a patch, so if you want to fix it, please send us the saved data where the problem occurred.
If you tell us which character you want to restore, we will fix it and return it to you."
This makes it sound like he is unable to patch the game and can only do it on individual basis with each player's save game. It might be a weird translation or my reading comprehension has gone bad.
I don't think, really don't hope, that he's just somehow unable to fix the bug itself. That'd be a crazy thing to just shrug off!