Action Required: Irregular activity in AWS account

Hello, I was notified that my Amazon Web Services Account email has been updated today with a new email address: XXXXXXXXXXXX

However, I have never updated my email address and my original email has never received any authorization email to authorize the email update.

1. I am not able to access my original account for now.
2. I am unable to manage the account and start remediation actions

As my credit card is required to be input when I register the account, I am worried the hacker will purchase services without authorization.

Would need help to resolve this issue, thank you!

*Edit: Removed email address — Ben G.