The Illinois attorney general’s office sued the owner of a Chicago remodeling company almost 30 years ago, accusing him of taking money from property owners for work that was either shoddy or never done. Without admitting wrongdoing, Mark Diamond agreed to change his ways. But authorities say Diamond merely changed up his scheme, continuing what amounted to a nearly three-decade career of scamming hundreds of people — primarily poor, older and black — with home repair and mortgage-related frauds …