Bantz with your mates

On my road to proving myself as not toxic I may have slipped up. The ally Tahm kench misplayed his Kalista skillshot or however Kalista works, and then proceeded to blame me for feeding. So I laughed it off and told him to accept his misplay, and the fact that i lost lane had nothing to do with how bad he messed up. He began flaming but i kept the light hearted attitude until i muted him because I realized he wasn't having fun with it.

Anyways, where do you draw the line at banter?