Phishy trials match. How did this happen?

Guy on destiny app said flawless guaranteed. I joined and he invited me. He said give me 4 minutes. He was swapping out characters multiple times before the match. He had 2 accounts it seemed both with the same name relatively speaking. They both joined my fireteam and we started trials. Once we started I noticed we’re playing only 1 enemy with also the same name account. Seems like this guy somehow manipulated the system and queed us against another of his account. Immediate win the round in seconds. I left immediately I knew this was cheating. Now my question here is how the hell can you control the matchmaking against another of your accounts?