Agile Actors .NET Software Engineer interview questions

After an introduction call (45 minutes) with a HR partner which included company introduction, review of my current position, salary expectations for the interviewed position and a few technical questions, a code assignment was sent to me, to be completed in a maximum timespan of 4 days. I completed and sent the assignment result on time and waited for the results. A week later, I received a call from the HR partner stating that there will be no offer, as there is a high discrepancy between the expected salary I asked for in the introduction call, and the one they can offer. If so, why even bother giving me the assignment? They did not even provide any constructive feedback on the submitted code, makes me doubt that they even reviewed it!