Such thing depends entirely on the system/application/host you're using, each one is different. But surely you'll find the answer reading the documentations of your host or whatever.
- Ricardo
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
Delete the account he created and change the password of your account because he knows it. Maybe change the username of your account, if possible, for extra security.