Suit to challenge liability to payment.

Where a notice of demand has been served upon the debtor or his authorised representative under section 4 the debtor may, if he denied his liability to pay the dues, penalty or costs or any part of any of them institute a suit within six months from the date of service of notice of demand, after depositing with the prescribed authority the aggregate amount specified in the notice of demand under protest in writing that he is not liable to pay the same. Subject to the result of such suit, the notice of demand shall be conclusive proof of the dues, penalty and costs, mentioned therein.