1. Contact the maintenance fund management organization: ask whether the invoice has been issued and the mailing status of the invoice. The management organization will provide corresponding inquiry methods.

2. Inquiring about bank transaction records: refers to the maintenance funds paid by bank transfer or electronic payment. Query the bank transaction records and check the payment amount, payment date and payee information.

3. Inquire about the records of the property management company: through the maintenance fund collected by the property management company, you can contact the property management company to inquire whether the payment has been successful and whether the invoice has been issued.