If the invoice has been used up or has not been used up but has expired, go to the tax authorities to check the original invoice and re-purchase the invoice.

Invoice-for-voucher: a special voucher issued by the tax authorities to the inspected units and individuals when the issued invoices need to be transferred out for inspection during tax collection or invoice inspection. The invoice exchange certificate has the same effect as the invoice transferred out for inspection. Units and individuals who have been transferred out to check invoices shall not refuse to accept them.