Soundwave interview questions

I got contacted through LinkedIn by the Co-Founder (I had no previous contact with the company before) to see if I was interested in this position. I answered back after 3 days and I had a brief chat with him through Skype, the co-founder was nice and correct but he had no specific questions on data science, it was like a cultural fit interview. I decided to continue with the process since I really liked the product and the co-founder seemed nice. He sent few questions about music-related content and had to solve them, find academic articles about music... Lots of work if you take it seriously. There was no deadline though. After three days I sent back my results in a very clear and nice format. After waiting two weeks without any response I decided to sent a follow-up mail to the Co-Founder but again no response (and I'ts been more than a month since then). What kind of company (actually, the co-founder) ask you to do some work and not even get back to you after sending several mails? Very disrespectful.