Someone using my apple account for FaceTime?

They signed in Andy iPhone got a notification saying so. I've changed all my info but since they're signed in does that mean they're still using my account. I also kicked all devices associated with my account.Am I safe

If you've changed your password, they can no longer do anything on your account. They will be prompted to resign in on their device when they try doing something such as FaceTime again.

However, it is also important to make sure your email has not been compromised, as that may be how they are getting your Apple account password. Change your email password to the account associated with your Apple ID just to be safe as well.