Any idea for this? My crush is complicated and unpredictable?

I outing with my crush few days ago, received her message "Thanks for spending time with me, and thanks for your treat too." after came back home. Seems like she is happy in that day.

But from that day onward she start to ignore me.. I message her also she doesn't reply. Until today i first call her, pickup the call and have a short conversation...

But when i called her second time, she divert the call (probably off her phone)

Any idea for this? For me girls are always complicated. unpredictable. Sometimes I feel like she is play hard to get. Or perhaps she is awkward with me.
Any idea for this? My crush is complicated and unpredictable?
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