Status Mobile UI/User Experience Designer (Remote) interview questions

The interview consisted of a rushed video phone call with a man in New York who appeared to be working out of a We Work type shared space. He asked very few question and was quick to complimented me on my portfolio saying that it appears as though I have all the skills they are looking for. Then promptly asked if I was willing to perform a design exercise. While this practice is, in my opinion bordering on unethical, it's not uncommon. None the less, I accepted as I had time and was interested to see what the ask consisted of. I spent about 3 hours putting together a simple use case solution with crude wireframe mocks in a sketch file provided. I returned them via email and never heard back. Not a confirmation email, not a thank you, no feedback stating the work was unsatisfactory (which I am certain wasn't the case as I have over 15 years experience and the exercise was a simple linear chat sticker share use case).