Hello Billnotmurray,
thank you for posting on the Microsoft Community Forums.
I'm sorry to hear about the issues you're facing. BitLocker keys can indeed be tricky to recover, especially if they are tied to an organizational account. Even though your school IT said it's nothing to do with them, it's worth insisting and explaining that BitLocker keys for devices registered under their domain are typically managed by the organization. Ask if they have any administrative portal access to retrieve the key.
Additionally, you can try to find it by following the steps in Find your BitLocker recovery key - Microsoft Support.
**Important:**Microsoft Support is unable to provide, or recreate, a lost BitLocker recovery key.
Good luck,
Lei