Matchmaking with guest

Hey everybody,
I tried to play online with a friend as a guest of my account. This has worked for me since I bought the game when it came out. I was even one of the lucky ones who did not have online problems most of the time. After not playing the game for a few months, me and my friend keep getting kicked out of matchmaking after 5-15 seconds of searching. I called support, and did all the clearing and even factory reseting the Xbox and reinstalling the game. Nothing fixed the issue. Today when I called, the guy on customer service told me the patched it because it was never supposed to be like that, allowing friends to play with you… I’m calling bs on that. Halo was made to play with all your friends on one screen. Any help would be great! Thanks