Locked out of all school equipment

During Lockdown a child at school entered our school apple id wrongly 3 times and has locked us out of the school account and the icloud account. Unfortunately the member of staff who set this up is no longer with us and we have no knowledge of the answer to the security question. We have been onto Apple Support on the phone for over 12 hours on and off in the last few weeks and have been given absolutely no help at all. This means that we now have over 100 ipads and a mac air that can no longer be used as we are unable to log on.

Please does anyone have any help they can offer us to enable us to find a way to log on and be able to use the equipment again. I am at the end of my tether, they can tell me the password is wrong but cannot tell me how I can reset it without access to the information from the dead member of staff. Our head is threatening to go to the press with this story so I am now becoming desperate for an answer.

PLEASE any ideas?