Donnie was Volcana's fence.
Donnie had a deal with Volcana where she would steal goods and Donnie would act as middleman, or "fence" the ill-gotten goods on the black market, giving a cut of the profits to Volcana. After robbing a yacht club of nautical memorabilia, she attempted to supply Donnie with it, but he declined to buy. The "boat stuff", as he called it, was hard to sell. Volcana protested, and Donnie said that he was aware of her financial problems and would love to help her out, but he first and foremost needs to make money from sales to do so. Volcana agreed (eyeballing another potential robbery), and proposed to meet at "the usual place". Soon after she had hung up, Kurt and his underlings barged into Donnie's office. Kurt intimidated Donnie into divulging information on his illegal business relationship with Volcana.