Dunno about heart of stone, but she REALLY has it bad for Bani... Even in all her hurt about Anu being preggers and stuff, she couldn't let go of her hatred for Bani, never mind that Bani was ready to end her own marriage for Anu and the Walia izzat sake...
And yeah, there should have been more Jai-Bani scenes. That wasn't much of an apology (though I'm not sure whether Jai needs to apologize-apologize or not since Bani misled him- he had shown trust in her)... And no proper making up scene- just a few words- tumhe kahi jaane ki zaroorat nahi hai...