Call 12366. According to the provisions of Article 19 of the Measures for the Administration of Invoices in People's Republic of China (PRC), knowing that units and individuals sell goods, provide services and engage in other business activities, the payee shall issue invoices to the payer. Therefore, when selling goods, regardless of the amount, the payee must issue an invoice to the payer. Those who refuse to invoice can call 12366 to report.