Managed Google Play
For managed Google Play it seems the package name has to be globally unique, and other customers have already uploaded the business edition of FolderSync to their managed store. You can try to upload the APK but if it fails with an error, this is most likely the reason.
If you experience this issue the only option is to package the APK with a new package name. There is however some work that goes into building a new version of an app with a new signing key and providing updates for it etc.
For a fee or larger volumes orders we can offer to build an APK with a unique package name. Contact us to inquire further.