Sion Q and ult not activating? [GAMEPLAY]

Okay, so I was playing Sion in Nemesis Draft. Everything was going well until around the 30 minute mark. That is when I noticed my Q and ult would not activate at all. I would be at full mana without having the abilities on cooldown. I would just press Q and R, but nothing would happen at all! I could still activate Death Surge with the Q and R keys during my passive. Additionally, if I tried pressing Q and R during (actual) death the standard "This ability is not available" would pop up. It definitely was not my keyboard as I could still type with the keys. The unresponsiveness only seemed to occur while I was alive and continued for the rest of the game. Have not played Sion since but I was thinking of buying him, however this is a potentially game breaking bug as I could not contribute in teamfights at all. My other abilities worked just fine as did the actives for Ravenous Hydra and Randuins Omen. Please help.