I'm a victim of cyber bullying. They are monitoring my phone and I need help to stop it

A person on a site called Wattpad is repeatedly sending me terrible awful messages about how horrible of a they think that I'm. In turn they some how monitors my phone and can tell me the stuff I do, who I text, and what I text them. Not only that they somehow got access to my phone number and had someone text me as like a spy to see how I would react. They honestly hate me and they won't leave me alone no matter how much I ask. They believe that they are doing some sort of justice by harassing me and they won't stop until they believe I have changed from this image they see me as. Reason is not a option. I don't feel safe and my privacy has been invaded. I don't know how to get this to stop. I really need someone's help on how to stop them from monitoring my phone. I have a IPhone 6. Please and thank you.

This is when you need to go to the police

But can the police get involved if this is a internet related issue, though it has crossed into personal boundaries?

Terminate the phone, change your number, ignore the bullies, keep your chin up, enjoy life.

Go to your phone service they'll help you, or you can block the contacts and stuff, and also on wattpad.