Getting your twitter account stolen is a big risk because the intruder might commit identity theft. You need to deal with this problem before it gets out of hand.
Methods to recover your account:
1. Change your password
Change your password immediately from the Password tab in settings or click on request a password reset from the logged out page on twitter’s webpage. Make sure you select a strong password you haven’t used before.
Please note that changing an account’s password does not automatically log the account out of Twitter for iOS or Twitter for Android applications. In order to log the account out of these apps, you need to sign in online and visit Apps in your settings. From there you can revoke access for the application, and the next time the app is launched, a prompt will request that the new password be entered.
2. Make sure your email address is secure
Make sure that the email address attached to your account is secure and that you are the only one with access to it. You can change your email address from your Twitter app, on iOS or Android, or by logging in on twitter.com and visiting the Account settings tab.
3. Revoke connections to third-party applications
While logged in, visit Apps in your settings. Revoke access for any third-party application that you don’t recognize.
Please note that if you use the teams feature in TweetDeck, it is strongly recommended that you check the members list to remove any users you don’t recognize.
4. Update your password in your trusted third-party applications
If a trusted external application uses your Twitter password, you need to update the password in that application. If you forget to do so, you might be locked out of your account by failed login attempts, since these apps try to log in automatically.
Your account should now be secure, and it should be back to normal. If you are still experiencing issues, you need to contact file a support request on Twitter’s website.