QuantumBlack Software Developer (London) interview questions

Had a good initial phone call where we had a general chat about the role and myself. I was told that the following steps would be a code challenge done on hackerrank followed by feedback and an interview in person. I was repeatedy assured even if I performed poorly on the hacking challenge I would receive feedback. The process was quick to this point and the time between applying and coding challenge was about 3 days. On completion of the challenge I sent a follow up email to let them know I had finished. After no response, I sent two additional emails over the course of the following week but received no reply. Several months later I still haven't heard anything. Massive timewasters as I must have invested at least 5 hours into prep and the challenge.