Had a stalker. One "date" that ended after 35 minutes. I was able to text my sister and she called me pretending something bad had happened. Pictures didn't match the online profile. Also more or less, I got the "this girl is crazy vibe."
She didn't take the hint so I blocked her. She kept getting new phone numbers. I documented everything.
One day, me being nice, figured I should finally just tell her in person I wanted nothing to do with her so I agreed to meet in a public place. We met at a pizza parlor and she sets her purse on the table and opens it to reveal a handgun. I changed my tune and went to the bathroom and called the cops.
Turns out she had gotten my personal info when I was unconscious in hospital and had targeted me from the beginning. She went to jail for felony stalking and lost her job as a nurse.
Edit: I want to use my top comment to provide my advice. In any situation document everything. Screenshot messages. Screenshot you phone call list. Back them up somewhere else besides your phone. The easiest way to stop harassment stalking is to to get a temporary protection order and then a restraining order, and/or a no contact order and screenshots and detailed documentation makes it easier to obtain one.
This is not legal advice. Just personal advice from personal experience.