In-person conversations are usually best if you’re in a relationship with the guy. This conversation will probably be hurtful to him, but it’s more polite to confront him in person and give him the opportunity to talk to you about it instead of sending a text or a Facebook message. If you’re friendly with the guy, talking in person or over the phone is probably better than an impersonal message. If you don’t really know the guy or he makes you uncomfortable in any way, don’t meet him in person. A text or Facebook message will do the trick. Try to provide the guy with a simple reason for why you do not want him to call you. It’s usually better to say something that has something to do with a lack of compatibility instead of insulting him with personal attacks. Saying, “I don’t want to see you anymore because our personalities are not a good fit for one another” is better than saying, “I don’t want to see you anymore because I think you’re lazy and stupid. “[2] X Research source

If you never want to hear from him again, make sure he understands that. Don’t send mixed messages by saying you can still be friends if you don’t want to be. If you are trying to maintain some kind of relationship or friendship with the guy, but you don’t want him to call you as often as he has been, be sure to explain exactly how often you are comfortable talking with him. Some guys will keep asking you questions in order to keep you talking to them. Once you have said what you need to say, you do not need to keep indulging him by answering his questions. Tell him you have nothing more to say about the matter and walk away. [4] X Research source If the guy does not abide by the boundaries you have set, it’s important that you don’t cave in and talk to him. [5] X Research source

Some guys might interpret any kind of response on your part as progress, which is why it is important not to respond to harassing calls in any way, even if it is just to tell the person to stop calling you. [7] X Research source

Some phone companies may not block numbers for you until you have filed a police report against the person who is harassing you. Keep in mind that this will only work if he calls you from one or two numbers. If the guy starts calling your phone from payphones or from his friends’ phones, you will have a hard time blocking all of his calls.

Keep your new number as private as possible so that he can’t find it. If it’s a home phone number, make sure it is not listed in the phone book. Also tell your friends not to give out your new number without your permission. You can also consider getting a second number to give only to people you actually want to talk to. You may be able to resume using your old number after some time. This method is also helpful if you want to maintain evidence of the guy’s persistent calls. If you don’t want to actually change your number, but you want the guy to believe that you did, you could try having someone else answer your phone or record your voicemail message for you. If you use Google Voice, the service will help you convince unwanted callers that you have changed your number by playing a message stating that the number is no longer in service to anyone who calls from a number that you have blocked. [10] X Research source

Stalking includes any actions taken with the intent to kill, injure, harass, or intimidate a person, and which cause a person to be fearful for his or her own life or the lives of others or to suffer severe emotional distress. If you are pursuing an kind of legal case against the guy who is stalking you, keep as much evidence as possible, including text messages and voicemail messages. If the laws in your state allow you to do so, you may also want to record conversations between the two of you to prove that you have in fact told him to leave you alone.