Before any attempts to create, make sure to search for any existing cases that can be of use. You can use the case to be able to transition properly, especially if the case was created in-between cases. If a new case is needed for creation follow the steps below
Search for the customer's contact information auto-populated in salesforce
Click on the latest contact information generated
Click on cases
Click on new
Choose inbound support
Fill in the information
Save
Once it refreshes it will allow you to send a new email
Close the case accordingly
Change the owner