Members of a Maine Army National Guard unit who recently returned from an overseas deployment will have to return at least $91,000 to the federal government after the military failed to stop paying them at their higher deployment rate upon their return.The unit came back from a nearly year-long deployment to Africa in January but were not notified until months later that the mobilization station in Texas where they were sent post-deployment had made an error and didn’t switch off their mobilization pay once they returned stateside. For more than 80 members of the Brewer-based unit, that means paying back between $325 and $3,600, according to Maine National Guard documents from March obtained by the Bangor Daily News. Some members have already paid off their debt, but two members who spoke on condition of anonymity for fear of retribution said the situation has made the return home for their unit more difficult, especially as members have come back to an economy that is much more expensive than the one they left. “This is a total slap in the face,” one member said.