Why was I banned?

This afternoon I was questing on my dk in nagrand when I was kicked offline without warning. I eventually got an email saying

Q u o t e:
World of Warcraft Account Notice - Final Warning

* * * NOTICE OF FINAL WARNING * * *

Account Name: ***********
Account Action: 72 Hour Suspension
Reason for Action: Terms of Use Violation - Economy Exploitation

Aside from making a bit of money on the auction house I don't have much impact on the economy and I'm not sure what I was doing that could possibly be considered exploitation. I mostly sell blues, cloth and enchanting mats, or items from leveling trade skills on alts. And frankly its rather upsetting that the gm didn't even bother to talk to me before banning me, especially as I have never before gotten a warning from a gm.

I created this trial account since I couldn't login on my own and created a petition asking for an explanation several hours ago, but I need to go to sleep so I am posting here in hopes of getting an answer. As I said in my ticket this account shares the same registration email as my main account.

Finally gm service has been more or less non-existent since 3.0. My guild had some loot mistakes made last Tuesday, the 20th, in naxx and several people myself included opened petitions to have it fixed and they were still open and there had been no word in the previous six days. I understand that the expansion and related bugs has created a much higher workload but thats a rather unreasonable amount of time to wait for a response to a rather simple request.

I hope that this is an exception and not the new standard. I have always had positive interactions with blizzard customer support in the past, even if they were not able to resolve the issue. Now it seems that someone did not take the time to so much as talk to me before, I believe unjustly, banning me. I greatly enjoy WoW and it would be very disappointing to see this level of service continue.