I can't see that you've done anything wrong, nothing wrong with a bit of networking and advertising. I've had other childminders email me directly to ask me to pass on their vacancies if I get any calls I can't accommodate, I'm fine with that. I wouldn't try explaining any further through facebook, but if you see them at groups/training/school/etc it might be worth explaining that you're sorry if there's been a misunderstanding, you shouldn't really need to but it might make life easier if you can smooth things over.