Manor College interview questions

I emailed the head of the department expressing interest; she replied the next day. I went to campus toured the classroom got the syllabus; I was given every impression I was going to teach; A week before the term starts I get an email: teaching not offered. I ask why: another applicant. Essentially the head of the department promised me the position then hired someone else while I thought I had the job. This works at the carnival but not at a business.