Global command to destroy all disconnected data files in Oracle 11g
Based on your description of this behaviour and your other comment, I guess your database runs on Windows.

The command you used should suffice and delete the datafiles. Except on Windows. On Windows, the datafiles are not always deleted, it is a known limitation.

Before dropping tablespaces or datafiles, take them offline:

alter tablespace ... offline;

or

alter database datafile ... offline drop;

And drop the datafile/tablespace after the above:

drop tablespace ... including contents and datafiles;

or

alter tablespace ... drop datafile ...;

If they still remain there, just simply delete them at OS level. And no, there is no such command thats deletes datafiles from the database that the database does not know of.

Reference:

Drop Tablespace Including Contents And Datafiles The Datafiles Are Not Automatically Deleted (Doc ID 389467.1)