Masteries broken to the point of unusable.

So yesterday, I picked up League again after a long break and tried some games with a friend. He told me some of the changes, and informed me that I should shift my mastery page. Upon trying to do so, I get the error message "An unexpected error has occurred" and it says it sent a bug report to the server. Okay, fair enough, my friend tells me it's been buggy lately, no big deal, right? Wrong. I enter the game with no masteries at all, and that costs me greatly throughout the game. Moreover, from that moment on, I could no longer switch mastery pages, as the same error would pop up. When restarting the client and trying, once again there was no masteries and an error message, every time I tried to do anything regarding my masteries. I launched the repair tool and tried again today, only to find that it did nothing, still showing the error message and leaving me helpless. There's not even an error code to help with this, it's just "An unexpected error has occurred" each time with nothing to explain with.

I really wanna get back into league, but with this kind of bug, I can't play anywhere near as well, and it just ends up frustrating me.