Students For Education Reform interview questions

I went through a process of 3 interviews, each about an hour long. The last was at their headquarters in New York. I also had to complete a performance test that took a lot of work over the course of 4 days. Everyone at the company was nice and respectful during the interview process. They then told me that they would reach out to me about whether or not I got the job within the next week. They told me this in person and then in a separate reply to my thank you note. It's been over a month and no one at the company has responded to a single one of my emails. They fully ghosted me. I understand not getting the job, I was even prepared for it as a recent graduate. But after over a month of interviewing and putting so much work into a performance test, it comes off as incredibly unprofessional to refuse to send even a one-line email to someone telling them about the final decision. It was a lack of common decency that left me with a bad taste in my mouth.