A Call From Unknown Number

This is really a big issue That "A call from unknown number", who are they? for what they are calling? this two question are very important. For example if you attend the call of unknown number and when you ask that who are you then suddenly he will reply that would you like to friendship with me, and your answer  will be 99% No. because if you are a male and male unknown will ask you for friendship then your always will always in negative, but what happens if the same number will call you but this time he is using voice changer and this time he want to show you that he is a female, now what will be your reply? its really hard to forecast the answer because different peoples have different ideas and have their different asnwers, but the main question is that why he is wasting his time? i have the perfect answer of this question, actually if your answer will in positive and you reply that why not we can be a friends, then he start chatting with you, and then he will come to his main point where he will starts blackmailing you, after that he will say you that send me this amount of money otherwise i can do any thing, and finally he will achive their goal,
So my suggestion to every one that do not make friendship with unknown numbers.do not give your information to unknown number,and do not wast your time in this kind of activities.