A complaint has been filed by the Nevada Gaming Control Board against CG Technology, the operator of seven sports books in the Las Vegas area, for underpaying approximately $700,000 on over 20,000 winning bets.

According to a Las Vegas Sun report, the complaint, which was filed on Monday, also states that over and beyond a three-year period, more than 11,000 parlay wagers were overpaid by about $100,000. The complaint also alleges that the sports book operator initially attempted to block the investigation by the state.

CG Technology conducts horse racing betting and sports betting at several casinos, including the Hard Rock, the M Resort in Henderson, Cosmopolitan, Tropicana, Palms, Venetian, and Silverton.

The complaint alleges that those winners who complained about being underpaid did receive their full payment, but that the same wasn’t the case for the thousands of bettors who failed to complain. For each of the complaint’s six counts, the company faces a $100,000 penalty in addition to disciplinary action being taken against the company’s license. CG Technology has been given 30 days to respond to the complaint.

According to the complaint, it is alleged that the incorrect payments began in August of 2011 and went on until March last year. The Gaming Control Board said that in May 2014 it was led to believe that the problem had been taken care of.  But in March 2015, an individual who had wagered notified state regulators that he was paid less than what he was due on a winning round robin parlay wager at the Silverton casino. He also said that on four previous bets he was underpaid and then reimbursed. The complaint states that a board investigation “revealed that incorrect payments on various winning parlay wagers had been a recurring and company-wide error for several years due to a software issue or software issues known to CGT.” It goes on to say that only after the investigation was started by the board were steps taken pay the company to identify all of the parlay wagers and the patrons who were affected by the software issue.

Steps to correct the issue were taken by CG Technology on or about March 9, 2015.