HelloFresh interview questions

Amazing experience, hiring person very professional and easy going. Questions were related with the position and about the right personality to fit this position. They called at the time they said.

3rd round. As a designer, I have received a huge test task related to a product (!). When it was reviewed, I received a delcine without pointing on reasons. Is it honest to ask candidates work 6-10 hours for free and not giving even feedback back? I can't appreciate it. It's not appropriate to act like this.