Get a hacked account back?

You contact minecraft support. Be prepared to prove you own the account, ie: you have the email address the account was registered to, or you can prove to them how you paid for it (credit card, paypal, etc.). They will reset the password for you, giving you back control of your account.

https://help.mojang.com/...was-stolen

As Neerp said, you'll need to contact Mojang's MC support team. As Neerp said, be prepared to give proof that you indeed own the account, which card you paid for it, card #, etc.

You need to contact the Mojang account support team.