A punter’s group has accused British bookmaker William Hill of deliberately delaying – or even avoiding – the payments of winning bettors by brandishing its terms and conditions of its withdrawal procedures.

Justiceforpunters.org has called on the UK Gambling Commission to conduct a thorough probe on the rules set by bookmakers on paying winning bets, which the group finds to be discriminatory, according to The Guardian.

The group’s founder Brian Chappell cited the case of a successful punter who was forced to wait nearly a month to be paid £13,000 (US$ 15,963.61) in winnings. He said the punter, which the news website declined to name, sought his help to withdraw about £20,000 (US$ 24,559.40) from William Hill.

According to Chappell, the supposed bettor opened an account with William Hill in mid-July and deposited a total of £7,100 (US$8718.59) over the course of the next four weeks, and placed a series of mostly three‑figure bets on racing.