A FORMER debt collector was jailed for 21/2 years by the District Court yesterday for offering advantages. Yiu Yim-kwan, 27, reversed his earlier plea of not guilty to two counts of offering an advantage between February 1, 1991, and February 28, 1992. The prosecution offered no evidence against him on a count of possessing implements fit and intended for forgery. Yiu's counsel, Mr Newman Wong, told Judge Hawkes that Yiu had been in financial difficulties. He had turned to two friends, a senior credit card administrator and a credit card administrator, both now in jail, and offered them $18,800 and $5,000, respectively, in return for details of credit card holders. The information would then be transferred to an underworld figure, counsel said.