Jarrell Miller says he is "outraged" after returning positive doping tests in successive fights and insists he should not be banned for life.
The American heavyweight, 31, failed tests before a fight with Anthony Joshua in June 2019 when three banned substances were found in his system.
He was due to fight for the first time since then on 9 July but again tested positive for banned drug GW1516.
"No-one can be more outraged than me," Miller told Fight Network.
"I am the one who has lost millions of dollars and has his career on the line.
"There is information that will come out eventually. I have made mistakes, big ones, losing financial rewards with the Joshua fight, which hit me hard. I know I messed up again with the world watching.
"But why the hell would you think I would go back and do something repeatedly, knowing that I'm coming back in my return fight with the financial setbacks and the hardship I am dealing with in my life? I want the general public to think about that."
Miller, who has not fought since November 2018, was due to fight American Jerry Forrest in Las Vegas and has apologised to promoters Top Rank.
He says his team are investigating whether a substance he ingested was contaminated.
Eddie Hearn, who promotes Joshua, says Miller's career is "over", adding: "I don't think any credible promoter will ever let him fight again."
But Miller said he should not be banned for life. "I am prepared to accept my suspension and do my monthly testing but be banned for life, no you are out of your mind.
"What has happened is sad - I'm angry but there is an explanation for it. Me and my team are working on it."