If your account got bannend you can contact the BYM support.
They will check your account for some different playstyles. If they are seeing that there are some ugly things happend, like 1sec build of many buildings you will nevery get back the BYM account.
The only thing is create a new FB account and play legit starting from zero.
a little tipp:
if you are using this swf file. after logging in into BYM build some stuff, upgrade some buildings. Not more than 5 per hour. Dont create much monster. And take care of the campion.
I tried to speedup as fast as i can and my fb testaccount was bannend after 45 minutes of speedleveling. got 34 levels in 45 minutes. that was funny.
now i login every 1-2 hours and doing some stuff. than logout and wait 1-2 hours.
Another tipp: try to use a different ip adress for your "cheating account" if they take a look for the same adress again it can be happen that your main account will be bannend too :)
Priezs can u make dreamteam hack on facebook :D