Upstox Senior Software Engineer - Java Developer interview questions

They gave me an assignment, which needs to be submitted in 2 days. I was having few doubts, on which they said do as per your assumption. I completed the assignment after spending 8-10 hours. I got rejected (which is ok, but that too was informed to me after many follow ups) I asked the company for my feedback. I had spend a lot of time in their assignment, so I think I should know where I couldn't fullfil their requirement. ( Because they didn't have time to clear my doubts in assignment, So i wanted to know how they have evaluated me.) But they never gave me feedback. I had wasted my weekend in their assignment