A customer had upgraded their free Google Apps to Google apps for Work Trial and wanted to cancel the trial 5 days before the trial ended. In the process of attempting to cancel the trial they were unable to downgrade from ‘Google Apps for Work Trial’ to ‘Google Apps’. There was no option to downgrade back to Google Apps, rather a ‘Cancel and Delete everything’.
During the trial the customer had added some additional domains which were preventing the downgrade option being available, as soon as the additional domains were removed the downgrade option appeared.
This can also happen if the primary domain is changed during the trial as well.