IVY Mobility Android Developer interview questions

There was 3 rounds (Technical, Project Manager and HR) All were online. I have cleared all the rounds and there comes HR's and his superior work into the picture. HR and superior done some negotiation(by telling company perks and benefits) to bring candidate expected salary to down till what they can offer and later they started telling everything is set, sent approval for releasing offer letter in parallell they have asked to believe in them and there company with some trustworthy words and made me to put resignation and there onwards they have started not responding to my call and emails. They don't know value of time. If some one belive's in them and accepts their offer by resigning to current job then they will be left in half a way. They wont bother about candidate. Seriously don't attend interview's and make your time waste and risk your current job. False company with bad HR and Immoral behaviour