Friend connectivity issues

I cant connect to 1/2 of my friends that play Halo 4 either in game joining, private chats, or party chats, always states connectivity issues or request to join timed out. This has been a major issue since the release of Halo 4, it got “fixed” then it started happening again. And before anyone tells me that its a NAT issue it IS NOT. All my friends have open NATs and Microsoft Networking Support stated that it was not a personal issue…is there any way to fix this or even have it acknowledged as an “Issues being investigated” because this is a big problem that i cant connect on XBL to a friend that’s only a few miles away but have no problems connecting to other countries?