Welcome to the forum!
Your status has been upgraded so you can post freely
As for your issue, I would NOT be answering the phone and next time I would send a short note home with parents prior to any vacation or off days that says that if it is not an emergency do NOT call as a vacation or off day means NO work.
Dear Daycare parents
During my recent vacation, I was bombarded by phone calls from parents regarding child care and issues relating. I would like to take this opportunity to let you know that from now on, during any vacations or days the child care is closed, I will not be accepting phone calls that relate to work.
You are free to leave a message on my voicemail or answering machine if it is an emergency and I will get back to you.
Thank you in advance as I am sure you all understand that a vacation means not having to think or deal with anything work related.
Sincerely,
Daycare Provider