I was also faced the same situation, i have done the assignment and shared all the files with them, i got a good feedback, but later i don't know what's in their mind, they not even replied to my mails and when i tried to calling no response and they blocked my number. what a worst company. if the person is spending 1 week for their assignment, they should reply back. may be they are taking ideas from the candidates and later implementing those ideas. better need to follow their projects.