Lilly calls cameron to invite her to a party, leaving the message on cameron's voicemail. after two days, cameron still hasn't returned lilly's call. lilly might interpret this as what type of response?

I believe the answer is: impervious.
impervious refers to a situation when an individual could be completely unaffected by the social stimulus around him/her.
In current social trend, many people often do impervious.behavior in order to be considered as 'cool' and raised their social status.