Lightroom CC: Switched from 1TB to 20GB. Although I deleted all the pics in CC I still have 286GB in the cloud which gives me sync errors

Switched from 1TB to 20GB plan. I had synced 450GB within the 1TB plan. Now, although I deleted all the pics in CC I still have 286GB in the cloud which gives me sync errors. How do I get rid of the 286GB? Not a single pic is currently stored in CC.