While the reform card may have only shown one game, they don't necessarily show all games that a player was reported in. Obviously, I don't know anything about your account, being that I do not have access to that information/am not with Riot, so there may have been previous reports on your account that simply were not included in the Reform Card. The RCs show recent matches, so if you had any that were older, it's possible that they weren't shown. Or, you may not have had any. I honestly have no idea. Have you had any chat restrictions prior to this ban? I see where you said you haven't been banned before, but they will escalate up to a ban if a player receives multiple punishments in a short time span (typically chat restrictions) or if they are showing a pattern of progression of behavior.
And while there is nothing outright flaming in this match, there is a fair bit of negativity in it. The first report category encompasses negative behaviors, not just verbal negativity. Behaviors like farming your own team's jungle so much that you put your jungler so far behind that it made sure that he had an item deficit. Even the Smite Support Singed and Nunu didn't farm their own jungle to within ten neutral minions of their jungler, nor did they steal the first buff from their own jungler at level one. It really doesn't look good when you do that, and then have this "Tissoulis: when i said i play onmly jungle" in your logs. It makes it look like you tried to switch roles, he said no, and then you went out of your way to ruin the match. Whether that is what you did or not, in the future, I would recommend not taking smite and feeding your own team's buff to the enemy top laner. I see plenty of matches where you played Blitzcrank as a support in your match history. So, you do know how to play a conventional support. You may not like it, but everyone has to support sometime. It's a part of playing the game.
One last thing to keep in mind, I'm not sure what was said in the pre-game lobby as this "Tissoulis: so u may lose quicker as i told u in the lobby" is the only reference to it, but that doesn't look very good. And while the lobby chats are not provided with the Reform Cards, they are stored, and can be reviewed by Player Support. If something was said that was particularly bad, and the players happened to screenshot it, it's possible that they submitted it in along with their report in the post-game lobby. The IFS is what sends you the Reform Card, but if the Support Specialist reviewed your case and read the pre-game lobby and saw something elaborating on throwing the match, they likely would not have looked too favorably on it.
and 
had under 40%.
Sorry am I not allowed to be talkative in the game? I'm very social and I like talking with people. we will get banned now because we are talking a lot? I need help to get my ban lifted!
