Single draft ban

I’m new to the game, almost 400 hours but there is one thing that I can’t understand. Firstly let me tell you my story, I was playing turbo game and went afk for 5 minutes maybe? And later I got banned because of this and now I’m in low prio and can play only single draft. The thing is that for players like me this is f up... I don’t know everything about the game, most of the heroes are unknown for me. Plus players on low prio are just f trolls. Volvo just why, this system is so bad... can we please smash that subscribe button?