Boy problem

Ok so last year my bf dated this girl (which I really don't care about because I barely knew him and stuff and we weren't dating) and this girl texted me saying that she wants to kill me for "dating her man" when then broke up last year. And on her birthday she started posting stuff calling me a skank and a slut and swearing at me on he snapchat story for everyone to see. I sent them to my bf and he didn't do anything about it he just said "have fun with that" so like idk what do I do???