Hi there! If you're definitely sure those weren't alliances, here are three tactics to avoid cheating:
1. Play Automatch, people can't cheat in Automatch.
2. Play 1v1 games.
3. When you play more than two-player games, steadily increase the player limit from two to 6 so that you don't get two cheaters joining.
You shouldn't have to fall in ranking due to cheaters. Your reports are reviewed and cheaters are banned. There is nothing else we can do, we ban cheaters that are reported.
If your ranking hasn't been restored, either:
A) The players weren't cheating.
B) The staff haven't gotten to that report yet (hundreds are filed every week)
C) It wasn't a noticeable amount of ranking points