When the governing body of such town levies a tax upon the property within such town for the purpose of paying such indebtedness or any part thereof and interest thereon, such governing body shall have the authority to levy a tax at the same rate and for the same purpose on the land so disconnected. The county treasurer shall pay over to such town all moneys collected by him on account of such tax, to be applied only to the payment of such indebtedness. In case the owner of any land so disconnected pays off and discharges a portion of such indebtedness equal in amount to the same proportion of the indebtedness which the valuation for assessment of his land bears to the entire valuation for assessment of all the property subject to taxation for the payment of such indebtedness, calculated according to the last assessment previous to such payment, said land shall be exempted from further taxation to pay such indebtedness. Upon such payment being made, the canceled bonds or other evidences of payment of such portion of said indebtedness shall be deposited with the treasurer of such town, and a certificate shall be given by him stating that such payment has been made.