Isn't it a bit of a stretch to go from "I can't log in to Bitstamp" to "Bitstamp closed my account without warning" without actually hearing anything from Bitstamp to explain what has happened?
wouldn't then at least the "forgot password" option work as in sending me an email?
This is why i assume they closed it... unless the forgot password recovery option is not working on their site.
I doubt anyone hacked my account because he would have to get access to my gmail which the history details do not show.
If i had a trojan on my PC, i am sure he would have gone for my btc-e account rather than the bitstamp one..
edit: But maybe you are right and i am jumping too fast on conclusions. I sent a mail to support waiting for a response to solve this mystery