Files moved from old oc install & their ownership/permissions

I had to re-install ownCloud on my hosted server because the old installation just quit working all of a sudden. I chalked it up to the server admins & since they now have an ownCloud installer via softaculous I decided to try it. Now running oc version 10. I've recreated my old user, with the same name, & moved files from the old data folders to the new ones but I can't see any of them when I log in. How can I change ownership of my old files to the user in my new cloud instance?

Assuming this could be done via the occ command line, how would I go about this? files:transfer-ownership seems to move existing files from one user to another, at the same time changing ownership. My files are already on the server, but not owned by any current user. I hope this makes sense. If this was a local file server the problem would be solved with chown.

I would recommend you to follow the backup and upgrade process: Backup database, Data directory and config.file from old server.
Start on new server with the same owncloud version, than upgrade to latest release bevor you upgrade to version 10.