Compare Microsoft 365 Support Options Assistance for billing and subscription management issues is available online signage company or by telephone during China business hours (Beijing Time), Monday through Friday. Billing and subscription management support can be accessed using the same phone number and online service request process as with technical support. The support telephone number can be found on the Microsoft 365 operated by 21Vianet portal. 2 Severity A is only available to customers who signed an advanced online service agreement with 21Vianet through a sales account manager. For billing and subscription management support, the highest severity level is B. Presales support for Microsoft 365 operated by 21Vianet provides assistance on subscription features and benefits, plan comparisons, pricing and licensing, and helps to identify the right solution to meet your business needs. See the table below for the type of support you can get depending on your product. 21Vianet assigns a severity level to a case when it's opened, based on an assessment of the issue type and customer impact. We can help you find a solution or connect you to technical support. You must be an admin for a business subscription to use these support methods. In most countries/regions, billing support for Microsoft 365 for business products and services is provided in English from 9 AM-5 PM, Monday through Friday. This service description uses the generic title administrator to refer to all categories of administrators.