Locked out of account after unusual activity detected

I received notification back in July 2026 that there had been unusual activity on my main email account. I tried verifying my identity but didn't receive a response. The mobile number is a number I've not had for over a decade so can't use that. The system sends a code successfully to my alternative email address.

I set up a passkey about a month before this happened, the system accepts the passkey and the password but still wants me to verify my identity; it just doesn't recognise the information.

I have tried verifying my identity daily since then - despite being told I'll receive a response in 24 hours I've never heard anything back.

I have tried an old phone, laptop and PC, every single one has logged me out stating the same unusual activity and asking me to verify.

I'm stuck in this endless loop but there's no way to trigger a response. What is I doing wrong? Everything is in this email - my work contract, my mortgage details, credit card details, car loan paperwork, you name it so I need access to this account.