Banned in firefight

So I was playing firefight doubles, after 1 game the second would always get me a disconnected from server error message. I kept playing despite those warnings, cuz it’s not my fault. Then all of a sudden I got banned. How is this posible?
I mean I understand it in multiplayer, but in firefight too?
Also, is there a way to fix this? (the disconnection error after a game)