[Mobile] Memorie

Go to https://assets.adobe.com and look in the Deleted section - files are permanently deleted after 30 days. If you had a lot of files in Adobe Express and deleted them there they may well still be sitting in Deleted taking up space. 

Also, if you use any other Creative Cloud apps check your storage here too:

https://lightroom.adobe.com
https://documentcloud.adobe.com
https://express.adobe.com/sp/
https://new.express.adobe.com/
https://assets.adobe.com/mobilecreations
- in the Mobile Creations area also check Deleted items.

Here's the help article about cloud storage and what is included as you may use other parts of it e.g. Libraries or Lightroom, that you haven't mentioned here:
https://helpx.adobe.com/creative-cloud/kb/file-storage-quota.html