Norton on Line Backup storage

Hi

 

why is my online storage showing I have exceeded 12gb when my backup is showing I am backing up approx 1.6gb in total from two computers?

 

I have tried deleting all files from one computer but the storage is still showing full!!

 

I have been unable to find any solution to this in any help pages and I note a solution to this problem has been requested before with no satisfactory response which is a worry?