Game Crashes

My game continually crashes whilst playing, this has caused me to be deemed as an AFK Buster even though its not entirely my fault the client just shuts down in the middle of gameplay or champ select. I even checked several times if my internet was the issue and disconnection was causing problems but my wifi isn't as I can easily load YouTube videos and web browsers. And even when I've connected to my mobile data, it still crashes or stops in the middle of champ select. Please help as I don't want to be on low priority queue time again.