Expedia Group interview questions

I was called for onsite interview. It had two rounds. I answered all the questions in round 1, they were ranging from simple design of application, simple data structure and algorithms. CSS HTML. Round 2 was - "Show me your CSS3 skills, and make the webpage fancy". Round 3 was skype round consisting of Java and javascript questions. HR confirmed me that i was selected and they will release me offer letter in 1 week time,k because they are big company and it takes lot of process and asked me to submit the required documents. I submitted the documents, but 1 day before tentative(email) joining date, they told me i was not having required documents and we cannot proceed further. In fact the actual problem was that they would have kept multiple people as backup, with different joining dates, as soon as their required number of people joined the company they declined the offer to all the people whose joining date was later on. They would have done this with multiple people. This is a fraudulent and unexpected behaviour from a company whose has reputation in market. So be cautious, offer from Expedia means "nothing", because at last moment they can decline the offer. Actually they were