[CLIENT] Can't do anythng but move and scream my hatred when using Veigar

There is nothing more infuriating than being able to do ... nothing. I can move about, and write in the channel (poor germans had to cope with my nerves break for about 15 minutes now) and that's about it. I choose Veigar and for the 4 first minutes I could actually throw spells. But then, nothing anymore : spells won't cast attacks won't work I don't see attack animations except that of minions I can still see other people / bot move around

I joined in a PvP 5 vs Bots Summoner's Rift game with Veigar. That's about as specific as it gets. I've tried killing my client and launching it again, under the pain of a temporary ban (for which I could hardly care less, as being banned would result in pretty much less unnerving results). I am disappointed.