Only jitspoe can fix this for you. He will have to straighten out the account activation id. When you join a game, press ~ and then type players into the console window, press enter. This will give a list of all players in the server and their player id numbers next to it (if they are logged in). If you see your player id up there then you're good to go.
The reason that you can play in a server with clan tag is because that particular server doesn't require you to login into the global login server to play on it. Most team servers are set like this.
