Help Someone Is Stalking Me!!!!?

[Jay]

Okay, so i have an iPhone 5 and somehow this girl keeps texting me and I have no idea who she is. Her area code is from Ohio and she found my number from my girlfriends instagram on a photo of us from 28 weeks ago. That is the only time I have given my number on a social network. I already deleted the comment with my number and double checked my account to make sure. But she LITERALLY texts me every 5 minutes calling me honey, babe, hot stuff, and sexy beast and asks if im okay 1,0000000000000 times if i dont reply INSTANTLY. I havent replied in over a day now and since ive been typing this up shes texted me 8 times. she texts me LITERALLY all night long like she doesnt sleep and its driving me crazy!! Me and my girlfriend already blocked her on instagram. My question is, HOW DO I BLOCK HER NUMBER???? PLEASE HELP ME!!

NOTE: I am NOT calling the police or the FBI just please tell me how to block her number. she hasnt called only texted
I have told her countless times to leave me alone but asks why im upset at her and says im too sexy. I am NOT calling the police or the FBI