You griefed a grieftrap. The ban will lift in 7 days (May 18th -- CST)
You made the mistake when you should have stopped. The grieftrap gives you a chance to think, "Hmm... should I really be doing this," before it bans you for breaking multiple blocks.
I hope you learned a valuable lesson from this. Do NOT touch or modify anything that does not belong to you or that you DID NOT make.
Moved to SMP Ban Appeals