Some trackers share ban lists among each other.
They cannot get your mac address.
You should go to ptp's irc channel and ask them about your account. You might get it back.
Use different names, emails, even ips and other details that you can think of for your accounts. Also, use another browser for your trackers.
That's about it if you're paranoid and want to be as safe as possible.
Good luck!

Really good info!
Thx