Four Plum Borough volunteer fire departments have resumed services as normal Thursday night, following a several-hour pause sparked by confusion over the borough's workers' compensation insurance status.The four departments, Holiday Park, Logans Ferry, Renton, and Unity, had suspended services effective 2 p.m. Tuesday after their respective chiefs grew concerned that the borough had not paid its insurance bill."We made a decision to protect our volunteers," said Carey Cole, the fire chief of the Renton Volunteer Fire Department. "It wasn't anything against the borough or anybody else. It was just out of precaution for us."Unity's volunteer department posted on Facebook Tuesday night that it was out of service and would not be responding to calls. The post went on to say it was working with the borough in hopes of resolving the issue.Allegheny County told Pittsburgh's Action News 4 that they had been advised to log equipment out of service for Plum's four fire companies, adding that other available units would be dispatched to calls in those communities.Pittsburgh's Action News 4 had a crew inside the new Plum Boro Municipal Center Tuesday night when officials with the borough and fire departments emerged from a closed-door meeting.Michael Thomas, the Plum Borough manager, said the departments had resumed services at about 8 p.m. He explained that the departments had decided to suspend services after learning that the insurance bill was not paid, fearing that coverage had lapsed.Thomas explained that he believed the coverage had never lapsed, but admitted the bill was not paid."I don't know if everybody's aware," Thomas said to the assembled journalists. "But we recently moved locations."Thomas said the state invoice, which had been due Dec. 31. Despite having completed paperwork with the U.S. Postal Service to forward mail to the borough's new building, Thomas said the invoice from the State Workers' Insurance Fund had not arrived at either location -- the old municipal building or the new one."It's kinda hard to keep track of every single invoice that comes through," Thomas said. "And actually, we didn't get this one. We never received this invoice."Thomas said he did not learn about the invoice due at the end of December until Jan. 4, when he was told by the borough's insurance broker. He said that the invoice was addressed, but could not be approved until the borough's council met Monday night.Thomas said the check was mailed overnight and out of an abundance of caution, the borough opened a second insurance policy. "I do apologize to the community for the concern, the frustration, the scare, the fear that maybe they felt," Thomas said. "I do apologize for that."Inside the new municipal building, the fire chiefs said they were just glad to get back to the status quo."A mistake was made," Cole said. "Mistakes happen. It was rectified in a timely manner and we're all back in service."This is a developing story. Stay with Pittsburgh's Action News 4 for updates. Download the WTAE mobile app to stay connected with breaking news.Correction: A previous version of this story listed the department services stops as starting Monday. This has since been corrected.