We hope you don't mind us replying in English. Just to confirm, do you mean that a family member is logged in on and using an old account of yours?
If you have access to the registered email address of the account, you can simply use it to reset your password and log out everywhere from the account page. Just make sure you log in on the right account.
If this is not the case, please let us know some more details about what's going on and we'll gladly help.