You should not do anything illegal. Any sort of physical violence should only be used in self defense. It should also be proportional to the attack received. You can't just end a persons life for punching you. You must respect the law, or you will go to jail. Check your constitution to know your legal options. But generally speaking, unless your life is in imminent danger, you will go to jail if you take things out of proportion.
My advise is to report this to the authorities and let them handle him in a legal way.
If you are competent in magick you could either only protect from him, bind him or destruct him. This all has levels to it, and depending on yours, you should do what you can to protect and possibly get your vengeance. Although, in my opinion it should also be proportinate to attack received.
All of these can be found in the meditation/witchcraft sections of the TEMPLE OF ZEUS website.
In addition, you have to choose wisely who you tell about Zevism. Christians and specially yehuborim who pose as christians can be very smart when it comes to tricking you into believing they are your friends only to screw you later. They will take advantage of your good intentions. If you are not open enough you may fall for this. Be careful next time.
"Do not mention my name nor my attributes, lest ye regret it; for ye do not know what those who are without may do."
Satan, Al Jilwah