(Wine-Searcher) - Rudy Kurniawan's lawyers have described the claims of some of his victims as improper and unreliable.

Convicted wine fraudster Rudy Kurniawan is disputing some of the monetary claims his victims have filed – including one for more than $15 million.

While Kurniawan, a 37-year-old Indonesian national, concedes that he needs to make restitution to both billionaire businessman William Koch and Philadelphia philanthropist Reid Buerger for $2.1 million and $192,000 respectively, his lawyers dispute the $15.1m claim made by former Quest Software founder David Doyle and multimillion dollar claims by other victims.

It took a New York jury less than two hours to convict Kurniawan, once considered one of the top five fine wine collectors in the world, of wire fraud and mail fraud. Prosecutors branded him "a prolific wine counterfeiter" and a man who made millions of dollars by selling bogus vintages concocted in his kitchen laboratory. Their latest estimates put his victims’ losses at more than $30.5m. They have sought to have him sentenced to up to 14 years in prison and fined $175,000.

Kurniawan’s lawyers have requested a sentence of time served – the 28 months he has been held in custody since his arrest on March 8, 2012 – and a fine limited to $12,500. He is now scheduled to be sentenced on Thursday, July 24.

Doyle, who is reputed to have his own a $40m wine cellar, has become a restaurateur, backing Australian chef Neil Perry in his Rockpool Bar & Grill restaurants. Doyle, who splits his time between California and Australia, hired Susan Twellman as estate manager. Among her duties was buying and maintaining Doyle’s fine wine collection, according to her affidavit, which prosecutors filed with the court on Friday.

"Boiled down to its essence the Twellman affidavit amounts to nothing more than an 'unnamed someone I hired told me the wine I bought was counterfeit.' This bald conclusion is, in its present context, the hornbook definition of unreliable hearsay," Kurniawan’s lawyer, Jerome Mooney, wrote in response.