The WBC champion claimed to have offered Joshua a guarantee of $50m (£36.2m) for the fight to go ahead, setting a deadline of Thursday evening for terms to be agreed.
That cutoff point has been and gone, though, and Hearn admits that negotiations have now taken a "bizarre" turn, which he believes is down to Wilder's bluff being called.
"It's all very bizarre. I returned the email of Deontay Wilder and said we are very interested in making this fight, please send us a draft contract," he told Sky Sports News. "He replied and said 'you have to accept the fight and then we will send you the contract'. I've never known anything so bizarre since I've worked in boxing.
"I had a meeting with Shelly Finkel scheduled for Thursday, he cancelled that meeting. I requested a meeting for today (Friday) and he emailed me, while also emailing the entire press world, saying 'there is no point in meeting it would be non-productive - we have to accept the deal first.' It's always nice to call someone's bluff.
"What we've done is called their bluff here, and they won't even meet to talk about the deal. It's bizarre, but we are talking to other people as well. There's probably about 50 people trying to make this deal at the moment. You've got Shelly Finkel, Al Haymon, Jay Deas and other people. When I was on stage I had texts from two people who I had not spoken to for about a year, saying 'I can help you make this fight'.
"We asked for a meeting to try and talk about the offer - they rejected it. We asked for a contract - they rejected it. I don't know what more we can do, we can continue trying. I believe the boxing world has realised that this was a PR stunt turned disaster. We do want the fight and conversations will continue. Dominic Breazeale tweeted this morning 'I have been told I am fighting Deontay Wilder in August'. Is this whole thing a bit of profile building for Wilder? We hope not, we want the fight."
Wilder insisted earlier this month that he would be happy to fight Joshua in the UK if he had to.