PichursParent,
It's hard to tell from your description, but there is a rule which might (or not) apply.
3-3-1 A coach, player, substitute, attendant or other bench personnel shall not:
....
o. call “Time” or use any command or commit any act for the purpose of causing a balk; or
.....
This rule is intended to address the situation where a pitcher is induced to stop his pitching motion, and if the umpire judges that this violation has occurred, it is a delayed dead ball. So if the pitcher stopped his motion in response to the coaches call of "balk", an umpire may decide that the coach's action induced the balk. In that case it is simply no pitch. The penalty is ejection, but you won't see that enforced very often.
However, in your situation it is quite possible that a balk had already occurred before the coach said "balk", and in that case the ball is already dead. In general, umpires are trained to make calls with deliberate speed, and so spectators sometimes think that an umpire has been "talked into" a call, when in reality he was just using good timing.