An NYPD cop who said he joined a violent robbery crew targeting drug dealers to pay his mortgage was slammed yesterday with 20 years in prison by an outraged judge. Officer Jorge Arbaje-Diaz emigrated from the Dominican Republic at age 19, earned a college degree and joined the NYPD in 2005 - then disgraced his badge because he couldn't make the monthly payments on a new house. That lame excuse didn't sit well with Brooklyn Federal Judge Nicholas Garaufis.