Is this email from blizz' real?

Got this email today, tittled "Illegal Transactions Warning"

"Greetings

We are very sorry to inform you that your account occurred in the number of illegal transactions in a very long period of time. We have not received any complaints about your transactions. But if other players send complaints about your account to us, we will permanently ban your account.

So we have issued this warning letters to you. You should go to the account management website to check your account status as soon as possible(http://us.battle.net/account), you can also find them here.

Sincerely,

Bill Mushkin
Blizzard Entertainment"

If this is real i cant believe it. I been hacked once but never done anything i shouldn't.