Denied.
He didn't try to ruin the game on purpose. I agree it was somewhat inappropriate to pause the game in the middle of a fight, but there is no rule about pausing so unless it can be categorized as purposeful game ruining we can't ban for it. We've talked about adding a pause rule, but it's such an extremely uncommon issue that it's hardly worth the trouble.
Consider this too: Slark wasn't in the team fight, and it must have been just as difficult for his allies to control their heroes at is was for you, so perhaps it didn't make that huge difference.
