If any person, without reasonable excuse, the burden of proving which shall lie on him, neglects or refuses to refund--
         (a) any amount paid to him in respect of a money order by an officer of the Post Office in excess of what ought to have been paid to him in respect thereof, or
         (b) the amount of a money order paid by an officer of the Post Office to him instead of to some other person to whom it ought to have been paid,
such amount shall be recoverable by an officer of the Post Office authorised by the Post Master General in this behalf from the person so neglecting or refusing as if it were an arrear of land revenue due from him.¹