If you experience that certain customers or date ranges are not available to select when you are building reports, this could be due to your Sales Data not being up to date. This is how you can update them, so that they become the missing customers or unavailable dates range are available:
Go to Import & export
Go to the Sales data tab and click on the Import button
Upload you most recently updated version of available sales data
Go back to the Reporting tab and click on the New report button
Start creating a report by importing sales data
Go through the different steps as you normally would
Now, while creating a new report, you should be able to make reports where your most recent updates are added.
Should anything still be unclear, then don't hesitate to reach to [email protected] - then we will gladly assist you!