Client freezes on champ select

So i have a problem where my LoL client freezes on champion select. mostly when the timer hits 0. I've contacted riot and all they say is that my internet is the cause. yet i dont have any problems with any other game/app. I have lost 8 of my promos bcuz of this. can someone please for the love of god help me.*i can restart it by ending league process but then it will not load completely into the lobby