Scroll to the bottom of this page and click on support.
Then click on contact customer service.
Fill out your email address.
Product: PlayStation Network - Account/Password.
Topic: Banned Account.
The rest should be self explanatory. Keep in mind that it is nearly Christmas, so it may take a while to get a response. I'm not sure what the holiday schedule is for Sony support, but their sales and distribution is usually closed from Xmas through New Years, so you may not hear back from them until after the holidays (hopefully it won't be that long).
Or, if you would rather call, click on Contact Us on the bottom of this page and you will see this:
Sony Computer Entertainment America
M-SAT 6:00 a.m. - 8:00 p.m. PST
Sunday 7:00 a.m. - 6:30 p.m
800-345-7669 (800-345-SONY)
Goos luck, and Happy Holidays.
Everyone thinks I'm psychotic (except my friends deep inside the earth).