He wasent stealing it, the federation kindly didn’t charge rent for utilities or for repairs. Sisko used that as leverage on him in "the bar association."

Quark is summoned to the captain’s office, where Sisko tells him that he wants the strike ended and things back to normal, so Quark is to sit down with Rom and hammer out an agreement by the end of the day. Quark says that Sisko doesn’t understand; merely talking to a union violates the core aspects of Ferengi culture. Sisko says that he may not understand Ferengi culture, but he does know who holds the lease on Quark’s – the Federation. The Federation has been extremely lenient, not charging Quark for rent, repairs, or the large amount of power the bar requires but that ends today. Sisko then reads off a list of things Quark owes; five years back rent, maintenance requests and the drain on the station’s power. After some quick calculations, Sisko asks Quark if he knows how much latinum that is. Quark pales, says that it is a lot, and agrees to talk to his brother.