Trouble with Xbox on apartment complex internet (double NAT or no UPnP)

I recently moved into an apartment complex and have been having issues with the internet, particularly with my Xbox.

First, it told me that I have a double NAT, though I only have a router, so I guess the apartment complex has one before it goes out to all the apartments? I turned on AP bridge mode on my router and that fixed that issue. However, now it says that UPnP was not successful and so I have a moderate NAT. I found that you can't turn on UPnP if your router is in bridge mode. I obviously don't have access to the complex's router, so I'm not sure what to do.

Any thoughts?