TORONTO -- The costly $616-million extension of Highway 427 north of Toronto remains unused by drivers as the consortium building the costly highway sues the provincial government for not getting paid fairly, court documents show. The Link 427 General Partnership says the province should declare the road finished, pay almost $145 million, and stop demands that it repave the road and do other work that it claims wasn’t required in the initial contract. “This case is about the government abusing its power to force the applicant to make costly last-minute upgrades to a major highway project without compensation,” the consortium says in its notice of application to the Ontario Superior Court.