s 56 Recovery of duty and penalty
When any duty or penalty has been paid in respect of any instrument by any person, any by agreement or under this Act or of any other written law in force at the time when such instrument was executed or first executed some other person was liable to pay the duty on such instrument, the first mentioned person shall be entitled to recover from such other person the amount of the duty or penalty so paid, and for the purpose of such recovery any certificate granted in respect of such instrument by the Collector shall be conclusive evidence as to the amount of the duty and penalty paid and the person by whom they were paid.