Were you doing account recovery? If yes, read this article: https://support.apple.com/118574
Did you use other equipment while the request was being processed? Note the two sections about how using devices while using Account Recovery may result in the request being cancelled automatically.
2) If the request was not canceled but you did not receive a message by the time anticipated, go directly to https://apple.com/recover Follow the directions to regain account access.
E.g.
https://discussions.apple.com/thread/256208323
Doesn’t have old telephone and recovery link is being sent to an address to which the person does not have access.
https://support.apple.com/118574
says, “If you don’t receive the text or call, once the period specified in the original email is over, you can still go directly to iforgot.apple.com. Follow the instructions to regain access to your Apple Account.”