Inaccurate disk storage

Hi All,

Anyone can help me figure out or resolve the issue? We have network storage (10TB free/50TB) after deleting the old backup with that we can at least have the space available. but in the BE console shows (46.5TB used/50TB). and that is not accurate to our original capacity which is (10TB free/50TB). It might also cause a failed backup and it turns out to offline status because it is already full.

Is there any resolution that might help us to resolve this? 

Thank you in advance.