Clear database for user and reupload everything

I updated my owncloud server from 8.2 to 10.10.4 and ran into several problems. I often get version conflicts and 403 fobidden errors now.
I only have one user in my owncloud (me) and want to wipe the whole server database for this user and just reupload everything again.
How can I do this?

Probably, you have some file permission error on your server. Anyway, if you have only one user, just setup a fresh installation and copy all your files data folder of your user. After that, use occ files:scan command. Here is the doc: