Ok, just for EU (german speaking)
I called them before I filed a ticket. (Got through after around 30 mins), explained my problem, guy looked at my account and told me "yepp, you are banned...but in this case I cannot help you...You are calling invoice-support...means that I can help you with RMAH or any other "money" related problems...I?d really like to help you, but I have no possibility to redo game bans, only game masters can do...and for that you have to write a ticket"...
Well I talked to him a bit, hence I knew that I will get an form letter with "fuck off" when doing so...He was pretty helpful and explained me in detail that every ticket will be looked into and bla bla bla...but thats it...
Oh and btw. I really wrote a long and extensive and charming ticket to get my main account back...but all I got was a form letter with "fuck off"

And yes, I tried for all of my accounts. Everytime I tried something else...from "stupiest" User alive to PC expert who built himself a new Linux system with hardware firewall a week ago.
Also tried to plea for x-mas amnesty and another one with "I think I fell for a phising email some days ago"...
Result="fuck off" on all accounts

So in my opinion if you got banned because of botting you are banned, no way to unban or amnesty in any way.
If someone get unbanned somehow he must have hit the "jackpot" somehow or is just trolling around