I received a speeding message saying that I would be punished within 30 days.

You must deal with illegal mail within 15 days, not 30 days. The parties concerned shall pay the fine at the designated bank within fifteen days from the date of receiving the decision on administrative penalty for fine. If the parties have no objection to the fines imposed on pedestrians, passengers and non-motor vehicle drivers, they may collect the fines on the spot.

Legal objectivity:

Article 108 of the Road Traffic Safety Law, the parties concerned shall pay the fine at the designated bank within 15 days from the date of receiving the decision on administrative penalty for fine. If the parties have no objection to the fines imposed on pedestrians, passengers and non-motor vehicle drivers, they may collect the fines on the spot. Fines shall be issued by the financial departments of provinces, autonomous regions and municipalities directly under the Central Government; If a receipt for the fine uniformly issued by the financial department is not issued, the party concerned has the right to refuse to pay the fine.