Final answer:
Microsoft usually reimburses customers for downtime by providing service credits.
Step-by-step explanation:
When a company's virtual machine (VM) is down due to an issue with the Azure infrastructure for an extended period of time, Microsoft typically reimburses the customer by providing service credits. These service credits can be used towards future Azure services. The amount of service credits given to the customer depends on the duration of the downtime and is determined by Microsoft's Service Level Agreement (SLA).