The Hammers boss was left visibly reeling after his side were denied a late equaliser at the death on Saturday, which he deemed should have stood.
Chelsea scored the winner in the 88th minute through Kai Havertz to make it 2-1 to the home side, but the Blues had soon thought their efforts had been undone by their London rivals.
Goalkeeper Edouard Mendy had beaten Hammers star Jarrod Bowen to a loose ball, but Maxwell Cornet was on hand to smash the ball into an open net.
West Ham went wild in celebration as they thought they'd equalised - only for the goal to then be sent for review by VAR and eventually ruled out after a check on Bowen's one on one with the Chelsea keeper.
After the final whistle, talkSPORT's Alex Crook - who was commentating on the game - confirmed Hammers boss Moyes wasn't letting the decision to rule out his side's equaliser slide.
"David Moyes has just angrily confronted Andrew Madley in the referee's room," talkSPORT's football correspondent tweeted.
"Safe to say he is very, very unhappy about the decision to chalk off late #WHUFC equaliser. Lots of expletives."
And when speaking in his post-match interview, Moyes was clearly still seething over the decision that saw his side fall to defeat.
And he also made sure to highlight that he believed Chelsea's keeper feigned an injury to get the goal checked.
"It's one [a decision] as bad as I've ever had," he said.
"For a decision to be overturned for that, I just find it incredible. I'm really disappointed VAR would even consider sending the referee to the monitor.
"But the referee then sometimes has to be tough as well. I've seen all the angles, I've seen all the pictures. The goalkeeper spills the ball, and if anything he then fakes a shoulder injury, which he did for the first goal to be fair.
"And he conned the referee into that, so there's nothing we can do."
When asked if he managed to have a construction conversation with Madley, Moyes was blunt.
"No, it was just such a bad decision you know," he said.
"So, no."
He continued: "It's difficult to talk about the game when you see such a rascally bad goal against you it's just unreal."