We can only point you in the right direction, we are just players like yourself here.
If you think your Account has been compromised, then you will have to telephone Sony Support for your Region, explain the details, answer some security questions to prove the Account is yours and they can do their magic tricks to get the Account back to where it belongs.
When you have it back, you might want to take up the added security protocol that Sony have....
2 Step Verification, a Code is sent to your Handy Phone (Mobile/Cell).
You use this as an added measure of security.