There was no hacking of your handle and you were not sharing it with Flynn.
Flynn was simply changing their username to imitate other registered members usually by adding a period at the end (jack.) so at first glance it *looked* like Flynn had hijacked an account but that's not the case.
(https://lulzplan.net/filez/Flynn_membernameChanges01.png)
Your ban was lifted but I would not blame you if you never want to look at this forum again.