Hello,
This is Tin, sorry to hear that your account has been hacked. I'll do my best to help.
First thing to do, please try to reset your password: https://account.live.com/ResetPassword.aspx
Please answer the Account Recovery Form:
There's a video included there for the exact steps that you should follow. Please make sure that you have a working email that you will use to submit the recovery form.
In case it didn't help, it would be best to reach the MS Account Support:
Thanks,
Tin