What should I do when a player intentionally feeds, gives up, goes afk with rage.

The last two ranked games my teams ADC raged early game. The first went afk and intentionally died multiple times during the game my team managed to push the enemy team and almost win game until MF decided to keep throwing herself into the enemy and giving them kills. At one point she even jumped on a full health tower alone and auto attacked it until she was finished off by an enemy. The second game the ADC raged when they played to aggressive and kept getting killed (trying to solo both the enemy adc and support) even though they played aggressive we had equal kills 10/10 even though she had 7 deaths. Instead of working with us she said "FF @ 20" and then started jumping into enemy towers and giving kills on purpose. When she was not doing this they began to auto attack jungle minions until the minions killed her. They initiated surrender every cool-down on it. We managed to get 1/2 last towers and almost win the game basically 4v5ing the entire time. But unfortunately the combination of free kills (17 deaths on her part) and time (Rumble and Nasus on enemy team) defeated us. What should we do when we encounter players like this? AFK buster does not catch them but they are still assisting the enemy team and might as well be afk. How does the report system account for these situations rather than just a bad player? I have no problem with unskilled players my problem is with people who ruin the game on purpose.