How to get rid of hacked account

You cannot.

If you believe that your Apple ID has been compromised: https://support.apple.com/en-us/HT204145

Then unless you have a very weak passcode and Apple ID password, or you gave them to someone, your iPhone is not hacked. Are you perhaps getting messages in your calendar about being hacked?

How do you know you have been hacked? Is your iPhone jailbroken?