Hearn is now pressing ahead with plans for Joshua, the WBA-IBF-WBO world heavyweight champion, to fight mandatory challenger Povetkin next, rather than Wilder, after demands from the WBA.
WBA president Gilberto Mendoza said his organisation had already granted Joshua and Wilder's teams an extension to agree a bout but said they now wanted a date for Joshua-Povetkin with "immediate effect".
But the WBA are exhausted of waiting and have now told Joshua he must fight Povetkin, their mandatory challenger.
The WBA originally gave the promoters of Joshua and Povetkin until May 5 to reach an agreement then extended the deadline twice because of a potential deal with Wilder.
Hearn sent Wilder a contract the American said he would sign, but nine days went by without the document being returned to Joshua. "That's all you need to know".
Deontay Wilder labeled Anthony Joshua a "coward a- b-" and accused him of being scared of committing to a heavyweight unification fight in an expletive-ridden tirade.
"The WBA has actually been very patient, but now they are pushing us to finalise this mandatory deal".
"If I wanted a fight, my fighter wanted a fight, and we received a contract, we would be back with the comments within 24 hours".
Wilder took to his social media late Tuesday night, tweeting: "I knew I smelt p-y but damn @anthonyfjoshua I didn't know the odor was that strong you coward ass b-h". This Wilder fight is one that has to get done and has to get signed. We just want your comments. "It's also odds on in this one that Joshua would win by knockout in the fight that everybody wants to see", added Aitkenhead.
They emailed me on Sunday and said we would be back with our comments on Friday.
"But the way they are going at the moment, I can't tell you whether this contract gets signed in 10 days or 10 years".
"The important thing for us is to maintain the belts and not be disrupted by people playing games or people who want to mess us about, because we're not going to allow that to happen to Anthony Joshua's career".