Coding4Youth Computer Science Instructor interview questions

Online resume submission. Required to make a 10 minute instruction video of a computer science topic of your choosing. Interview with technical questions. I was offered a job during my interview. However, the person interviewing me said I would also need to do a demo lesson that weekend, which he said was part of the interview process. However, I had already been offered the position. I clarified that the position was meant for the summer, as it was only March. The person interviewing me didn't allow me time to think about the offer. He also pushed very hard for me to teach the demo lesson in a few days. After our video interview, I got an email with a job offer letter. Less than 48 hours after receiving the job offer and without giving verbal confirmation or signing the offer letter, I decided to decline the position. I was subsequently harassed by the man who interviewed me. He called my personal phone. He sent me repeated emails telling me that I was highly unprofessional and that he would get me in trouble with my school. (The job was not affiliated with the university nor had I discovered it through my university). The pay is advertised as $12.50/hour. However, the fine print states this is only for hours spent instructing, so any prep time is unpaid.