Your ownCloud admin has the option to set a storage quota on users. Look
It may be helpful to understand how your quota is calculated. Metadata (thumbnails, temporary files, cache, and encryption keys) takes up about 10% of disk space, but is not counted against user quotas. Some apps store information in the database, such as the Calendar and Contacts apps. This data is excluded from your quota.
When other users share files with you, the shared files count against the original share owner’s quota. When you share a folder and allow other users or groups to upload files to it, all uploaded and edited files count against your quota. When you re-share files shared with you, the re-share still counts against the quota of the original share owner.
Encrypted files are a little larger than unencrypted files; the unencrypted size is calculated against your quota. Deleted files that are still in the trash bin do not count against quotas. The trash bin is set at 50% of quota. Deleted file aging is set at 30 days. When deleted files exceed 50% of quota then the oldest files are removed until the total is below 50%.
When version control is enabled, the older file versions are not counted against quotas. If you create a public link share via URL, and allow uploads, any uploaded files count against your quota.
Quotas Are Neither Hard Nor Soft
Quotas are not strictly hard quotas, but nor are they soft quotas either. They’re more hard quotas with the exception of always being able to restore deleted files.
Why? Well, say that a user’s Trash bin contains one or more files. The user uploads several files and in the process reaches their quota limit.
If hard quotas were enforced, the user would be prevented from being able to restore any deleted file. However, with the Trash bin exception in place, files can always be restored, but no new files can be uploaded, once a quota has been reached.
This user workflow may sound peculiar, but not allowing a user to restore files would make for a poor user experience. Given that, this exception is allowed.