Check the number of editors in your team: go to the team and Members tab, there you will see members of the team and the roles they have.
It’s possible that you accidentally added someone else as an editor into a file within the team, so you’ll need to pay for them. You will be able to revoke their editor access.
If the email doesn’t ask you to do anything, this is not phishing — Figma already has your card number and will automatically withdraw funds at the date specified in the email (~3 days from the day it was sent). If you think this is a mistake and/or you don’t remove the unwanted editors in your team before the date, you will need to reach out to the Figma support team via the help “?” in the bottom right corner in Figma → Contact support.