Digital Rocket interview questions

You apply for the job, your CV catches their interest, and they contact you to fill out a questionnaire. You complete the questionnaire, they like your answers, and invite you for an interview with HR. The interview goes smoothly, and you find the company culture amazing. Then, you get a task. And that's where the fun begins. The task involves creating a mini-brand strategy for a brand that, based on what I could see, is either struggling or one they haven't been able to help as an agency. It consists of 5 subtasks, each quite extensive. You write video scripts, provide ideas to improve the entire brand presentation, create several avatars, write hooks, receive a Facebook ad that needs a complete overhaul (all for the same brand), and create 3 thumbnails... And it's not just about spending days on these tasks; it's about not receiving a single response after such an in-depth analysis, not a single word from the two HR managers you were in contact with. To sum up: I've attended over 15 job interviews throughout my whole life, at various agencies, but this was the ONLY time I received such an extensive task and 0 feedback. Not even a 'thank you for your time' email. I'm pretty sure they exploit potential employees and their creativity through this type of task, without any intention of hiring. The job ad is still available on their site, 4 months later, and I am just wondering how many people have sent them their 'points of view', and how much free content they have received so far. To clarify, I am not against tasks, but I am against extensive, long, detailed, and time-consuming tasks that, in their perspective, do not even deserve 'thank you for your time and interest'.