My 20gb Cloud is almost full but only 170 Photos in My Photos

I inadvertently tried to import my full Catalog not realizing that Classic is more suitable.

Thus there is 19.88gb of 20Gb of storage taken up.

How do I delete everything from the Cloud as mostly using Classic.

Can only access 170 photos in CC on my desktop CC, IPAD CC and my Phone CC, how do I access the rest in the cloud.