The purported victim, John Gauger claims he and his company, Red Finch, were never paid the balance, even though Cohen later received $50,000 from Trump’s personal account, the Wall Street Journal reported.
The alleged incident shows how Cohen operated in secret to advance Trump's political fortune, the article said.
Gauger told the Journal that his work for the Trump campaign consisted of trying unsuccessfully to manipulate two online polls in Trump’s favour.
Cohen, who has been sentenced to three years in prison Special Counsel Robert Mueller’s Russia probe, for his part, responded to the article on Twitter.
"As for the @WSJ article on poll rigging, what I did was at the direction of and for the sole benefit of @realDonaldTrump @POTUS," Cohen said. "I truly regret my blind loyalty to a man who doesn’t deserve it."
Trump lawyer Rudy Giuliani told the newspaper that Cohen’s being reimbursed more money than he paid RedFinch showed the former Trump lawyer to be a thief and "completely untrustworthy."
The reports come as Cohen is slated to testify before the House of Representatives Committee on Oversight and Government Reform on February 7, where questions will likely focus on Cohen’s dealings Mr Trump over the years, including during the 2016 presidential race.