What do you do when you n-laws are out to get you?

Got married recently and the n laws(his mom side, not dad side) cant stand me. the mother never came to the wedding, the dad did. she sent people to come fight me, harrassing emails, text messaging, phone calls, etc. I got on that a** so she let me be, but now she is harrassing her son...I love him dearly but im to the point to where i wanna knock her...