SHOULD NOT BE ABLE TO CC YOUR ALLIES!!!

I just played with a support that went tahm after I told him not to and I was going 1/3/3 so he decided I was trash or something stupid and started intentionally spitting me into the enemy team. I CAN DO NOTHING TO STOP THIS. WAY TO ENCOURAGE TROLLING RIOT... What the fuck was going through the minds of the people that created bard, tahm, and kalista. WHY CAN YOU CC YOUR ALLIES?! WHAT THE ACTUAL FUCK!? There needs to be a way to escape an ally's ability that prevents you from being able to move where you want, riot seems to not give two shits about trolls though, but they will ban the people that flame them in an instant. Really corrupt system atm that trolls are going to take advantage of and it helps absolutely nothing to give them the power to make their team lose whenever they want to. Keep in mind this is a high plat mmr game, this shit happens all the time at every elo because trolls know for a fact that they will never get punished.