Why is he avoiding me?

well my guy-friend is avoiding me...He seems to be angry with me but I do not know why... When I try calling him his phone willl accidentally click off..... Although, i always get random calls from once amonth... My friend said he Ims her but they always seem to talk about me... we use to date...but I was the one to first say we should be friends...then when i liked him he wanted to be friends.( he had a girl). I really I am over it but he seems to po back in my life somehow..I havent called him in two moths