What did i do to her?

I have a cousin who is a year younger than me , since childhood we have been inseparable.The issue is that for about a year now i have not talked to her ,because she's changed everytime i would call she had to go someplace or sometimes her mom (my aunt) would say she wasn't home.Even one time she answered and as soon as i said hello she hung up on me.I have asked her what did i do and she says nothing i miss her very much , but am afraid to call her i'm afraid she'll reject me or worse.What do i do how can i get back that special sisterhood we had.