Core Points - China Unicom announced that the 400 customer service hotline will be discontinued starting December 26, 2025, to enhance service quality and provide a more unified, convenient, and efficient service experience [1][3] - Customers are advised to use the China Unicom customer service hotline 10010 or the Unicom App for inquiries related to services after the discontinuation of the 400 hotline [1][2][3] Summary by Sections - **Service Change Announcement** - The 400 customer service hotline (4000600611) will cease operations as of December 26, 2025 [1][3] - The change aims to streamline customer service and improve user experience [1][3] - **Customer Guidance** - Post-discontinuation, customers should contact the 10010 hotline or use the Unicom App for assistance [1][2][3] - The company expresses apologies for any inconvenience caused by this change and appreciates customer understanding and support [3]