Logan Paul has questioned Floyd Mayweather's claim that his wait to be paid for their exhibition bout is par for the course.
Paul took Mayweather the eight-round distance in their exhibition bout last summer - but no winner was declared.
The YouTube star has since claimed he is owed money by Mayweather, a sum believed to run into the millions of dollars.
Mayweather, who retired from the ring with a record of 50-0, claims he is still waiting to be paid for fights in his professional career.
During an appearance on The Pivot Podcast, he said: "This comes with the territory.
"To them, that’s real money, and I like the YouTubers. The money on the back end though, from pay-per-view, that takes a while.
"Nothing comes right away. I’m still collecting cheques from fights seven or eight years ago.
"They just hate when the table is turned. Be happy with the biggest payday you ever got in your life."
But Paul has responded to the boxing legend and doubts his version of events.
"I've not been paid in full, that is a fact," he said on the MMA Hour. "We're just trying to collect what is rightfully ours.
"He came out and said this is the name of the game, this is how it works in boxing but I don't know if it is, I don't know if that's true.
"I think after you fight you should get paid, it doesn't take this long to count the money.
"I don't know [how much it is] but I know it's not everything. It's large enough for me to make a fuss about.
'For the longest time I bit my f****** tongue. We heard it every week, 'The money's coming next week, the money's coming next week'.
"Three months in I realised the money's not coming next week, so I'm offended and I've been lied to.
"I never thought I'd be the 'Where's the money?' guy, but the only way to get this guy to move is to pipe up and embarrass him.
'It feels unfair and i just want to make things right."