GiveDirectly interview questions

I applied off the job board and got an invite to a take-home coding assessment on CoderByte that was *timed* to 45 minutes. I passed with 2 minutes to spare. I moved on to the next round which was a one-hour live coding interview. It was challenging and I didn't get through the whole thing (15 more minutes and I would have). I thought I did well enough to at least garner the third "Systems Design" interview, but I never heard anything. I tried reaching out to the two people who I had been in contact with, but nothing. Right after my interview, one of them switched to a "Briefly Out of Office" auto-reply, which persisted more than a week later. I'm wondering if I got put on some kind of blacklist. Anyway, the two interviews required a lot of prep and stress on my part and it would have nice to get some feedback, at least a 'thank you for your time and interest'. Feels very unprofessional to just get snubbed like this.