Lean Station Backend Developer interview questions

They reached out to me in a job portal. The hiring person asked a few questions about how early I can join them. After that, they gave a work a assignment to complete which was not much complicated and they gave me 10 days of time which was definitely a good amount of time. I completed the assignment in one sitting as soon as I got the time out of my regular work and sent them the completed assignment. That's it. That was the last time I had a message exchange from the company. They simply ignored messages after that. I tried reaching out to them later as well but no response. I don't really care about getting hired by them but a candidate at least deserves an acknowledgement with either positive or negative review from the hiring company upon the assignment completed. Definitely an unprofessional company.