I'm sorry you are going thru this, but I agree, it does sound like stalking. You've had to change your phone number!
I was the victim of a stalker which ended very badly. I did call the police many times during this experience, but it didn't help till he had broken into my house with a gun and tried to shoot me.
I don't want to frighten you, but if you are being stalked, you must do all you can to stop it, and follow the advice of the previous post to put an end to it by being cold hearted! Don't have any contact, as this just encourages them, even if your responses are negative...they still just keep coming back!
Once you have made yourself clear in a cold way, cease all contact. If this doesn't help the situation, then contact the police!