when a girl gives you her number woman opinions?

[djfree3000]

okay, so this girl was real nice i liked her and i asked for her number i told her i wanted to hang out with her and get to know her and to give me her number so i asked and she gave it to me she even stood around and waited to give me her number cuz i was busy doing something and she waited well i called her today and yesturday and yesturday she was like oh let me call u back and then 20 mins later i called her and her friend said she was sleeping i know it was a lie but i called her and she wont pick up what should i do? did she just flip her brain on me? did she do it to just get rid of me or what? i need to know cuz im sick of this happening all the time. what do u think ? is this natural for a girl to stick around give u her number and then just forget about u the next day or what? please help how do i get her attention or how do i get better results for the next girl i meet. thank you