I have had teams on the same level; this season I made sure they weren't in same league, it is not fair play but it's hard to prevent. I like the idea of friends not playing the last couple matches, but in some Leagues that wouldn't work: I'm friends with over half the league as are they, and not all the same, so that would be nigh impossible. Using such methods to win, I would think wouldn't feel like winning, for me anyway. All you can do is report it to Support and hope enough such reports prompt a change.