Activation lock issue
I have a 2022 Apple Mac Studio that I bought refurbished directly from the Apple website in January 2023, Applecare was taken out but has since expired.
I recently upgraded the MacOS from an earlier version - I think it was Sonoma - to Tahoe. The only reason I upgraded was because the latest version of Photoshop told me that my OS needed upgrading to work properly. Tahoe was a disaster for me - various issues including not being able to open dmg files, Adobe Lightroom acting up, and the machine not starting up properly (blank screen with cursor), it also refused to start up in Safe mode - the only way I managed to eventually get it to restart was by disconnecting everything bar the keyboard, screen and mouse.
Anyway, I decided to revert back to an earlier OS. Made sure my Time Machine backups were in order, made a bootable USB drive, and erased the Mac.
I'm now stuck on the Activation Lock screen. It advises me to log in using the email associated with the Mac, which it prompts as r*****@mac.com. I have NEVER has a mac.com email address. Tried my Apple ID email, no joy, tried my phone number (also on my Apple ID account) no joy, tried my device password - three times - and it then locked me out from further attempts.
The only thing I can think of is that the Mac was registered to this r*****@mac.com account before it was refurbished by Apple and sold to me. I've submitted an Activation Lock request but other than the acknowledgement email have heard nothing more. I've tried to contact Apple Support via the website but once I enter details of the issue I end up with a message telling to contact the original owner of the Mac to get them to remove it from their account. I can't do that because I bought it from Apple!
Looking online I am reading that it could be days or even weeks before I hear anything back from Apple. This is ridiculous... Has anyone got any suggestions? I've actually made an appointment in my local Apple Store for the weekend in the hope that someone there will be able to gee things along, but I'm not hopeful.
iMac 27″, macOS 12.6