BlazeClan Technologies Python Developer interview questions

Worst company I have ever seen. After clearing all interview rounds, they released offer letter. Again 1 week before the joining date, they scheduled client round interview and told that it was not cleared and so will not be able to onboard me. Please don't go for such a shameless company who don't have any ethics of hiring. Why do these companies play with emotions of candidates if they don't have any openings.