(a) When the office of constable in any township becomes vacant by death, resignation, refusal or neglect to qualify, or failure to elect, any constable of any adjoining township, during the vacancy, shall execute and return all process which are issued by any justice of the peace in the township where the constable's office is vacant and which are directed to him, against any person in the township where the vacancy exists.
(b) In addition to the fees now allowed by law, the constable shall receive for the service of each and every summons or subpoena, or other process, except executions, so directed to him, two and one-half cents (2½¢) per mile, going and returning from his own residence to that of the person named in the process residing farthest from him.