Sorry to hear that your account has been hacked.
Start by reading this to get your account back if you don't got access to it anymore: https://help.ea.com/article/i-think-somebody-hacked-my-origin-account-what-can-i-do-now. and http://answers.ea.com/t5/Battlefield-3/Account-Hacked-Compromised-and-Account-Security/td-p/1125370
If you do got access to it change your Origin password to something good ( https://strongpasswordgenerator.com/ ) that you don't use anywhere else and then do it again for the password to your email address.
Then read this to make sure it never happens again:
https://help.ea.com/article/how-to-maintain-account-security
Also, make sure to enable Login verification:
http://help.ea.com/en/article/origin-login-verification-information/
