If you have recently updated to a later version of Geneious than your license allows, you can downgrade back to your previous version of Geneious. To do this, uninstall the new version of Geneious and reinstall the version of Geneious that you were using previously. Older versions of Geneious can be downloaded from here.
Uninstalling Geneious should not delete your data as this is usually stored in a separate location to where Geneious is installed, however, you can first create a back-up of your database using the back-up button in Geneious.
When you ran the new version of Geneious for the first time you will have been asked how you would like to upgrade your database. By default, Geneious will upgrade your Geneious database to a new folder, leaving your existing database as a back-up. When you restart the older version of Geneious, Geneious should automatically pick up this previous database. If Geneious does not pick up this database automatically, you can manually point Geneious to this location by going to Tools→Preferences and using the Browse button in the General tab.
If, instead, you upgraded your existing database to the same location when you started the new version of Geneious, you will need to restore from an earlier back-up of your database.