Aston Villa boss Dean Smith was furious after their 2-1 home defeat to Brighton.
An injury-time penalty for Villa was overturned after referee Michael Oliver consulted the pitchside monitor.
Smith snapped: "I don't know what a penalty is now. We could all hear the contact inside the ground.
"If VAR thinks it's not a penalty then just tell the referee it's not a penalty. It wasn't given so we have to take it on the chin.
"I don't think we were bad. We missed chances and we've made big mistakes for their goals. We have to defend much better. Brighton were a threat on the counter but I wasn't overly concerned.
"I thought we had control of the game and if we had taken our chances we would have won."
Smith added: "I did want to see the officials after they said to come in and ask them but they scarpered before I got there.
"I don't think anybody understands what goes on in penalty boxes, what's a penalty and what's not now. I'm left scratching my head."