Spark No. 9 interview questions

They ghosted me after two interviews and an unpaid writing assignment. Didn't respond when I followed up with them. Within the first two interviews they had a mock brainstorming session with me about brand/product positioning strategy (which they told me went well), as well as a general discussion on my writing approach. Third round was a two-part writing assignment that focused on ad copywriting and positioning strategy, as well as writing an internal brand-focused social post for them. I was told that this assignment would be the second-to-last round of their interview process. I worked for several hours on their writing assignment, only for them to never get back to me. Just putting it out there that this is how they treat late-stage candidates.