unfamiliar with 7zip archive - Help!

[C.Tresenriter]

On Sun, 2015-04-12 at 09:46 +1000, Karl Auer wrote:

> What does the "file" utility report? Might not have been
> compressed/packaged the way you think they are, and file extensions can
> lie.
> 
> Email the sender and ask him *exactly* how he extracted the files.

I'm already waiting for a response on that question.
 
Here's the output of "file -z <file.7z.Z01>"
7-zip archive data, version 0.4 (Zip archive data, at least v2.0 to
extract)

and the 7z.zip file  reports simply:
data
Maybe I'm using the utility incorrectly?

Years ago I had another archive like this (7z.Z01. 7z.Z02, etc) with
several parts, I eventually decided I had spent enough time trying to
figure it out and gave up.