A student has intentionally changed my password locked out can't remember birthday or it has been changed
We are a large high school and we have a cart full of iPad minis. I created one generic icloud account for all of them. I mistakenly made the password available and now a student has changed the password that I used for all of them. I have no idea when this happened and I cannot change the password back because I have either forgotten what I put for a "birthday" or a student changed the birthday (can they change a birthday intentionally?) Either way I am dead in the water because I can't access the icloud email to receive the reset password. I know my challenge questions but I can't get to them because I can't get past the birthday question I am caught in catch 22.
I submitted a question to tech help but I have heard nothing in over 48 hours.
Thank you for any help you can provide.
Sincerely,
Matt P*****, PHS, Tampa, Fl.
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iPad Mini, null