Fragen im Vorstellungsgespräch für Beschäftigung als Algorithm Developer/Image Processing Engineer bei Iteris

Interview consisted of 2 rounds. Both the rounds it was on-site since I was living in Los Angeles. I was interviewed by the team lead, director of the company and HR on the first day. The second time they called me to interview with other team members and the vice president of the company. Everything went well, HR called me the next day and told that they have made a decision to offer employment and spoke about salary and other details and told me they would start paper work soon and give me an offer letter. I did not get offer letter for 4-5 days so after few days I contacted HR asking for offer letter and HR told they are yet to make a decision and now it's been more than 3 months and still I haven't got any reply from them. They did not even take care of my travel expenses or anything. They made me visit the office twice and did not even bother to send me a proper response. This is probably the worst company I was ever interviewed with. Once a candidate visits the plant for an interview HR will definitely send either an acceptance or reject. But I didn't get any decision.