Meta Front End Engineer interview questions

I applied for another position two months prior to being contacted about another position the recruiter felt I was more suited. The phone interview was typical recruiter conversation (CV, languages, types of projects, why I wanted to work at Facebook). I was then asked to complete a code exercise in JS or PHP. It involved sorting and arranging overlapping events on a day calendar like iCal. While I easily complete the exercise and accommodated for all stated and unstated event scenarios, I was told that Facebook was no longer interested after reviewing my code. I was quite surprised and requested additional feedback, but they did not provide it. I gave them several hours of my time to complete their test. The least they could have done was give me 10 more minutes of theirs.