Can anyone help please.

I have a shared excel document. This document is protected. 500 (or so)
rows have been unlocked starting at row 5.

I have sent the document via email to about 300 members of staff. They have
returned their spreadsheet to me via email.

Each spreadsheet has headings in the first 4 rows (which are locked) the
fifth row of every spreadsheet has been filled in.

When I have merged say 10 files into the original document, all 10 files
have inserted the data into row 5 and overwritten any existing data.

I did try this out before sending to so many people and it worked fine with
about 6 staff.

Does anyone have any ideas. I would be most grateful.

Thanks

A very puzzled user