Northern Light Health and Anthem Blue Cross Blue Shield agreed Wednesday to resume contract talks and keep the insurer’s patients from being out-of-network for some health care services. About 30,000 Anthem enrollees are Northern Light patients, including state employees and some nurses and firefighters. He said for some firefighters in northern Maine, almost all of the health care services nearby were Northern Light. The contract dispute heated up last week, with Anthem officials accusing Northern Light of walking away from mediation. Northern Light officials said they were willing to negotiate.