28. No document for which fee is payable under this Act shall be of any validity, unless and until it is properly stamped or supported by proper receipt. But, if any such document is through mistake or inadvertence received, filed or used in any court or office without being properly stamped or supported by proper receipt, the presiding judge or the Head of the office, as the case may be, or, in the case of the High Court Division, any Judge of such court, may, if he thinks fit, order that such document be stamped or supported by receipt as he may direct; and, on such document being stamped or supported by receipt accordingly the same and every proceeding relating thereto shall be as valid as if it had been properly stamped or supported by receipt in the first instance.