Can you please clarify - when you're asking for technical support, it is critical to provide a clear description of the problem, including the full text of any and all error messages.
* When you are disconnected - what error message?
* When you say you can't reconnect - what error message?
* When you say your other character are still on - what the hell does that mean? Do you mean your other *accounts* are still *logged in*? Or do you mean the character that was disconnected is still visible in game ? Or do you mean something different?
* How could there be problems with changing characters, if you've already been disconnected and can't get back on????? Or do you mean you get disconnected when you attempt to change characters on your other accounts? Or do you mean something different?