The goodwill built between Dustin Poirier and Conor McGregor appears to have passed.

Poirier and McGregor were cordial in the lead up to their rematch at UFC 257 and after the bout when “The Diamond” scored a second-round TKO victory over the Irishman in January to even the score between these two fighters.

The primary source of that aforementioned goodwill was McGregor’s public promise to donate $500,000 to Poirier’s charity, The Good Fight Foundation, ahead of their UFC 257 showdown.

On Sunday evening, Poirier responded to McGregor’s tweeted prediction of how things will go in their proposed trilogy fight at UFC 264 in July by saying that “The Notorious” never followed through on his word to donate that sum of money.

“That’s a fun prediction,” Poirier wrote on Twitter. “You also predicted a donation to my foundation and you and your team stopped responding after the fight in January. See you soon. July 10th Paid in full!”

This irked McGregor, who responded by saying that The Good Fight Foundation team hadn’t outlined how that money would be spent before he parted way with that $500,000.

“A donation, not a debt,” McGregor said. “We’ve been awaiting the plans for the money that never came. I do with all my donations. Know where it’s going dot for dot. Otherwise it goes walking. As is the case with a lot of these foundations, sadly. You took the [McGregor] over the belt shows I was right.”

Poirier’s rebuttal saw him claim that his charity’s inquiries were blanked by McGregor’s team.

“100% never a debt,” Poirier replied. “You offered, we accepted, and like I said your Team never responded to our emails regarding the process of where funds would be put to work! July 10th you will taste defeat yet again.”

Things stepped up a notch following the Louisianan’s retort. Perhaps angered further by these public allegations or mention of the fight, McGregor slammed Poirier and claimed he is going to “fight someone else” at 10 July instead of the former interim UFC lightweight champion.

“You’re ripped you inbred hillbilly,” McGregor wrote. “Why do you wink with your ears? You f*****g brain dead hillbilly. 500k with no plan in place. Ye hang tight. Fool. You must be new to money. The fight is off btw. I’m going to fight someone else on the 10th. Good luck on your old contract kid.”

The Dubliner then responded directly to Poirier’s last post on the matter, saying:

“My team does their due diligence to make sure every donation meets the mark. My generosity is known. You will pay with your brain for this attempt at smearing my name. Shooting ass shelling ass b***h. Little b***h kicks from a shell. Good luck when you’re caught. You’re f**ked.”

The pair then exchanged video and photos of their knockout victories over each other.

In the first bout, McGregor knocked Poirier out in the first round of their featherweight bout at UFC 178 in September 2014.