Contacting someone even after they said don't try to contact me

There was a girl she studied with me in school, recently we get connected with Snapchat and whatsapp again we talked day and night, We talked like boyfriend and girlfriend but she never committed to me ,we kept talking like couples. She made me obsessed with her, and suddenly she said she doesn't want talk anymore, I asked again and again but she blocked me from everywhere, I messaged her with 10-12 different numbers and now she is saying she will file complaint against me what should I do now.