I'm sorry for the rejection. Hopefully you (we!) get into Chicago! (I didn't apply to Harvard).
One thing though: you seem pretty sure that you've been rejected. Given that you have an MA in Economics, I assumed you are an international student, and international students do not necessarily get a call, right? Also, isn't the starting class at HKS 12 – perhaps there are other people not, mostly international, that have been or will be accepted?
Not sure about Oxford, I believe it will be quite competitive, since there are not too many PhD degree in Public Policy in Europe, and its a growing ''field''!