law: 56. Notice of payment of charges short-levied or erroneously refunded.-
  (1) When any Board is satisfied that any charge leviable under this Chapter has been short-levied or erroneously refunded, it may issue a notice to the person who is liable to pay such charge or to whom the refund has erroneously been made, requiring him to show cause why he should not pay the amount specified in the notice:
  Provided that no such notice shall be issued after the expiry of two years,-
  (a) when the charge is short-levied, from the date of the payment of the charge;
  (b) where a charge has been erroneously refunded, from the date of the refund.
  (2) The Board may, after considering the representation, if any, made by the person to whom notice is issued under sub-section (1), determine the amount due from such person and thereupon such person shall pay the amount so determined.