Yes. One should first attempt to know why that in question is not responding to someones' calls. If there is no possibility of reaching him. one should wait. This certainly pays and the misunderstandings will be cleared. In my view, waiting with a positive attitude will certainly pay.
It's a natural phenomenon. Any upset causes ripples of negative thing. At this juncture, humans first think in a negative way. Here the need is to have a grip on the situation of emotional turbulence. Positive approach does the needful.
Naturally.. If the person is really important in one' life, however busy or occupied otherwise he might have responded or he might have said that he is busy. But when this doesn't happen, there is no use of running after him and weeping.
Read each and everyone's point of view and I do accept your opinion. Still, I have to say that it is fine to remain positive but a person is bound to think that why did it happen. No response is also a response, is a great answer by @vijay and it signals that the other side is not keen to continue the relationship. It hurts because when one is not at fault but is subjected to misbehaviour is undoubtedly an insult. I must appreciate the answers of @suni51 and @Gulshan Kumar Ajmani who have indicated that self respect is of utmost importance. I too believe in this but still, I tried to contact them because I don't want to harbour any ill feeling. From today onwards self respect will be of prime importance in this case and nothing else.
@rambabu I am absolutely fine. My life does not revolve around them and I have far more important things to do in life. As we know that friends do have a place in life so it bothered me a bit. You see, with time it will die but yes, the prick of insult or you say disrespect will certainly be there because I am a human being and not an Almighty.