game froze in ranked matchmaking and i got banned for it

Heya,

You likely got connected to a match when your game froze up.
Depending on how long you were disconnected for, it's possible your match ended as your squad was eliminated / left, or something alike.

From what I understand, it's not really easy to detect if someone has a game freezing up / crashes, at least, not in a way that prevents people from abusing it.
It's quite easy to make an application freeze up via certain methods, so if Respawn/EA were not to penalize based on that detection, people could just "fake crash" and not get penalized.

The game freezing up can be caused by many different things, and in most cases isn't really caused by the game itself.
When the game was frozen, were you still able to interact with the rest of your Operating System? (e.g., Switch Tabs, Open task manager)
If possible, please attach a DxDiag to your post, which can make it easier for me and others to troubleshoot to why your game possibly froze up. Information on how to get a DxDiag can be found on this EA Help page: https://help.ea.com/en/help/pc/how-to-gather-dxdiag-information/