If the selectmen of any town fail, for a period of five days, to open, in accordance with the provisions of § 13a-107, any highway which is part of a rural free delivery route, any person or persons residing on such route may open such highway and shall be paid therefor by the town compensation at the prevailing rate of wages for such services; provided, if the selectmen have contracted with any other person to open such road, the amount paid by the town as compensation as herein provided may be recovered by such town from such contractor, unless otherwise expressly provided in such contract.