21Vianet also expect customer to collaborate at reasonable level accordingly. 21Vianet assigns a severity level to a case when it's opened, based on an assessment of the issue type and customer impact. Examples of issue types and severity levels are shown in the following table. Authorized administrators can use the Microsoft 365 operated by 21Vianet portal to submit service requests online and access support telephone numbers. We can help you find a solution or connect you to technical support....