To everyone who thinks that supercell matches you more often against cards that "counter you" or that it matches you against higher level players if you spend money.

STOP

This is simply untrue and supercell has public admitted exactly how their matchmaking works. Dataminers have found no evidence that they are lying.

Here is the original forum post question that they answered in a Q&A :

Q: Is the matchmaking rigged in any way, shape or form?

A: ‘Yes. For the most part, the matchmaking system is only based on trophy count. Decks and player XP do not come into the matchmaking system at all, so its not as if you will be forced to play with someone who has a counter to your deck. Its just that there are millions of players, so people are bound to have counters to your deck. However, if you are on a losing streak, the matchmaking will try to pair you with someone else who is on a losing streak, to help break them. The only other feature of matchmaking is dealing with trophy droppers, there are not many of them, but the system does try and pair higher level players with each-other in the lower arenas if possible.’