Hi milasx10,
We initially start out new accounts with a 512MB limit, and then, once the account has been active for 7 days and is using at least 50% of the disk space limit and follows the Terms of Service, we're able to give the account a free upgrade to Unmetered disk space on request.
It looks like you have hit your 512MB limit, which is why you are seeing this.

It looks like a lot of your space is used up by directories called "users" and "Users" (which are not be publicly available) -- removing these files might help with this.
Thank you,