(Wine-Searcher) - Few victims of “the biggest and most successful wine counterfeiter in the world” have come forward to either demand punishment or repayment and that is causing a conundrum for U.S. District Judge Richard Berman.

The prosecution provided a “conservative estimate” that Rudy Kurniawan, convicted in December of fraud, sold at least $20.7 million in fake wine. But defense lawyers for the 36-year-old Indonesian, who has been living illegally in the United States for more than 10 years, dispute the figure and put the losses closer to $8 million.

Kurniawan was due to be sentenced on Thursday but that has been postponed for another two months, as Judge Berman seeks to find out the true cost of Kurniawan's crimes.  “We need to know what the numbers are,” he told prosecutors.

Asst. U.S. Attorney Jason Hernandez replied that he would do his best, but “the difficulty we’re having is finding people (buyers) to talk.”

In his sentencing recommendation letter to the judge, Hernandez explained it was hard to arrive at an exact figure because “there are at least two of Kurniawan’s victims who each purchased several millions of dollars of rare wine from Kurniawan who have not provided the Government with any assessment or estimate of the fake wines they bought from Kurniawan.”