Own team banned my champ

So ever since I discovered Gangplank I've been playing him religiously in ranked, especially cause he seems to rarely get banned. I've had about a 75%-80% winrate on him in ranked, and my average KDA and CS is obnoxiously high as well. Carried my way from S4 to my promos to Gold in about a week.

So I'm sitting at 2 wins and 2 losses in my promos(Losses were due to AFKs, as usual) and I post in champ select that I main GP top or mid and link my stats. What does my team captain do? Bans Gangplank. So I try to be a good sport about it, and end up going to a position I'm not nearly as good at(ADC). 10 mins into the game, my top and mid have both died like 5 times.

I didn't do that great that game either, but I was struggling to do everything in my power not to tilt. Ended up losing the series. My question is, is it reportable when your team bans your own champion in champ select like this? Seems like unsportsmanlike conduct IMO.