Digital360 (Australia) interview questions

I had several phone interviews/conversations with HR, followed by an in-person interview with their Digital Strategist who was friendly and polite. I was then asked to do a four hour paid trial in which I produced a completed piece of work. After the trial I sent an email requesting feedback. They sent through detailed feedback, albeit weeks later. After this feedback email, communication from Digital360 ceased completely. I did not receive payment for the trial for more than one month afterwards. They used my piece of work for their client weeks before making payment for my trial. The payment for my trial then appeared in my account randomly after several emails following up.