[PLEASE HELP] Player intentionally feeds and trolls, somehow Riot decides to ban me?

What's up guys, last night I had a fun night of League until this player intentionally fed my lane. Here's the story: In champ select I selected Camille and he selected blitzcrank. We swapped (i thought as a joke) This player refused to give back my Camille. I was stuck with blitzcrank top, but, this didn't even bother me. I saw it more as a joke seeing as the player said 'hehe xd' when refusing to give my champ back. My friend and I laughed and I didn't say anything to the player. I started off the game by saying positive things in all chat because my focus was to win and have fun. All of a sudden my three teammates start flaming me for ''trolling'' because I'm blitzcrank top. I did not choose to play blitzcrank top but it's still not trolling to play off-meta. All of a sudden the Camille blames me in allchat for taking his champ and starts intentionally feeding their toplaner. I ask why Camille would do this seeing as he wouldn't swap back. I couldn't lane very well because Camille was running to my lane and constantly feeding. Then my entire team say's ''report blitz troll'' in all chat and flame me. Not once this game do I cuss or insult my team, I only try to defend the fact that I am not trolling. 10 minutes after the game Riot gives me a 14-day ban for being ''toxic''. Can someone please help me, I've sent a support ticket to Riot but I'm sure they will not unban me. How can they randomly ban me for nothing? EDIT: If anyone wants to see the chat I will post it here, I have nothing to hide.