A ban won't come for a single game .... at least you don't have a very cancer behaviour, but this has nothing to do with how you plaied
If that would happen (but it's basically impossible that it happens) you would simply contact the Player Support.
The difference is, if you go 0/12, but are still trying to lane, still trying to group, fight with your team, damage enemy champions, ward, pay attention as well as you can, they will know you are trying, and just genuinely had a bad game.
No such thing.