2 Yellow Cards

[Emorej Campo]

I have a question fellow players please educate me lol! I was watching my game just now and I saw one of my player got 2 yellow cards in the game. He was ejected afte he get his 2nd yellow card so I tried to replace him with a new player and it wont let me sub him? Is this a bug or this is really how it is on football? Sorry I'm not really good with football rules LOL. It also says I have +8 ball possession but the entire game the guy had 60-40. And after the game I checked the statistics it says 50-50? Please explain if you understand this. Thank you in advance!