Leidos interview questions

Very unprofessional interviewing process. I went through the face to face interview, and then waited for a week, in which I was told I would be getting an offer letter. However, upon asking them questions about the offer (which I did not receive any answers or responses to my calls from HR), I was told the offer letter was rescinded. Felt like the HR department was unresponsive and gave me quite a disappointment upon learning that the offer letter was sent, but was no longer available for me.