Why our Dua is not accepted?: Breaking relationship, sin, frustration and impatience.

In Saheeh Muslim from the hadeeth of Abu Hurayrah that the Messenger of Allaah (sallallaahu ’alayhi wa sallam) said, "the supplication of the servant will always be answered provided that he does not supplicate for something sinful or supplicate to sever the ties of kinship(Breaking relationship with relatives) and provided that he is not impatient." It was asked, "O Messenger of Allaah, what is impatience?" He replied, "he says: 'I have supplicated and supplicated but I have not received an answer' then he becomes frustrated and leaves off supplicating." [Saheeh Muslim [ Eng. Trans. 4/1430 no. 6595]]