I don't recognize the phone number required to access my Apple Account

I'm trying to access my Apple account that I haven't used in around 7-8 years. When I try to log in with my email address it prompts me to confirm a phone number ending in 27. The problem is that this is not my number, has never been my number and doesn't belong to anyone I know either.

Is there any way around this at all? I can't tell them the number because I have no idea what it is. It's as if the account has been hacked or something at some point while I've not been using it. Cheers!

[Re-Titled by Moderator]

Original Title: I don't recognise the phone number required to access my account