The software we use for our control panel (cPanel) has a hard limit set on the username of an account, of 8 characters. Therefore, the system automatically shortened your name to the first 8 characters so that it could be created properly.
Are you still getting stuck at the "Sign In Successful" page?
Glad to hear, if you have an issue again please update us with the exact time if possible, this will allow us to search the server logs to see if there is anything on our end causing a problem.