By "missing", can we assume that someone deleted it accidentally? Or what?
Could there be a backup version of the file, e.g. with extension .bkp or
.bak in the same folder as the original?

There is no built-in facility for this, but
a. how much data did you have? Was it small enough that it would actually
be easier to re-type?
b. what sort of output documents have you produced? Are they on disk? Do
they contain all or most of the data from your data file?
c. if your output documents are only in printed format, do you have a
scanner and OCR software?

For output in mailing label list format, Graham Mayor's article on creating
a data file may help:

http://www.gmayor.com/convert_labels_into_mail_merge.htm

Peter Jamieson