A former cocktail waitress at exclusive nightclub 1OAK is filing a class-action suit against the establishment today, claiming she was screwed out of tips along with other workers. Tarale Wulff, 33, says 1OAK tacks a 20 percent "service charge" onto their $450-and-up bottle service, misleading patrons into thinking they were "gratuities paid to the service workers." Instead, "a percentage [is] distributed to nonservice employees, such as doormen," according to court papers obtained by the Post. Wulff, who was fired last month after a dispute involving a customer's expired credit card, is suing for unspecified damages. Two years ago 1OAK was sued by four former employees, all minorities, who claimed club owner Scott Sartiano only wanted "white girls he could f---" serving drinks.