Cannot access recent activity page

I just got an e-mail from Microsoft account team saying that there has been something unusual about a recent sign-in to my Outlook e-mail. When I wanted to check the recent activity, they asked me to fill in a code that would be sent to my phone number. Unfortunately, I've forgot to change my old number, and now that I updated it to my new one, I have to wait 30 days to access my recent activity page.

What should I do now that there might be some creepers on my e-mail, but I can't access my recent activity page for 30 days?