I'm certain you aren't banned. You would have gotten one of those LM-17 messages that "Playonline Services have stopped".
Because of the timing, this sounds more like a simple payment problem and with the registration server down for maintenance, you might not even be able to get back on PoL until it's over.
You'll probably have to sit out the weekend, but I wouldn't worry about it.
I will admit, though, I've never seen that code before, and I once had my card expire and the message I got was LM-18 and it specifically said I needed to update my card. All I had to update was the expiration date though, the card number was the same. I just forgot to update it when I got my new card that month. Hopefully it's not a Special Task Force code for GTFO.
Ask yourself the following questions, though:
Did you share your account information with anyone? Hopefully you haven't just been robbed.
Do you play on console such as PS2 or XBOX?
If so, and if you haven't shared your account information, (Hopefully you have a Security Token), did you do anything such as harass or stalk someone that may warrant for action against you?
If you play on PC are you using Windower or any third party tools and did you admit to using any of these tools in the game to anyone?
Are you using any "obvious" 3rd party applications that affect your movement speed or allow you to hop to any zone and coordinates that you input?
Have you ever slept with another girl? If not, would you be interested and do you live in the United States?! Click my MSN button and add me!