My Creative of 20gb looks full but I use only 5gb! What is wrong?

In order to free up storage, you have to disable the photoshop presets feature as described here (chose NO when asked to keep the data in the cloud): https://helpx.adobe.com/ie/photoshop/using/sync-presets.html

then go to your cc web site by opening cc desktop app>clicking cloud icon>cc web empty all 8 folders (4 in your files, 2 in shared with you, 1 in shared with you, 1 in deleted).

note: if you delete from your sync folder, your local files will be deleted, too. this is the only folder that affects your locally stored files.

click the lightroom link at bottom left of your cc web page and delete files from there. lastly, recheck your deleted folder and delete whatever is there.

and if you need to contact adobe support, use a browser that allows popups and cookies and contact adobe support by clicking here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human

p.s you can also use phone (but chat is usually quicker), https://helpx.adobe.com/contact/phone.html

p.p.s. you can also use twitter to tweet @AdobeCare

p.p.p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true