Banned

Recently I got a permanent ban for the "use of scripts, hacks, exploits or unauthorized third-party programs in League of Legends." even though I haven't ever used any scripts,hacks, exploits, or unauthorized third-party programs. The only thing I can think of that is in some relation to this was a game I played a few days ago where suddenly I couldn't connect to the game, even though my WiFi was completely fine and working. I was only able to connect after the game ended and it showed me the end screen. Can anyone help me? Thanks.