Got banned for third party application?

I've been playing league of legends for 4 years and I have been playing legit and never touched hacks. Now all of a sudden im banned for third party application? I have been maining yasuo for a pretty long time and now all of a sudden im banned for hacking? Im a fucking bronzie, am i too good with yasuo that you thought i was hacking? I suck with him. I want to know which match that i was banned for.