It's not okay with the person or the person is not taking any bullshit.
When Jenna's hair does not look as it should, she's not havin' it.
The teacher said there was a pop quiz and Meg was not havin' it.
Ian was cut off by the car in front of him, he was not havin' it.
Dave has a really bad headache, so he would say "my head is just not havin' it right now".
Chelsea asked the teacher to go to the bathroom during the lesson, the teacher was not havin' it.