It sounds like your Apple ID might be compromised or that you have received a scam mail.
Please go to settings >your name on your devices, If there is still your ID displayed there, it is most likely a scam mail. Please reset your Apple ID password to be sure
If there is another Apple ID displayed, your Apple ID is compromised. Please see this
- Change your Apple ID password
- If your Apple ID password has been changed by someone else, reset your password.
- Go to appleid.apple.com to update any of personal or security information that isn't correct or that you don't recognize.
- Check with your email address* provider to make sure that you control every email address associated with your Apple ID. If you don't control an email address, work with your email provider to regain control or use a different email address.
See this link for further reference
If you think your Apple ID has been compromised - Apple Support