'mail was returned' is a correct and usable part of a sentence in written English.
For example, you could use it in the following sentence: "I sent a letter to my old friend last week, but unfortunately the mail was returned."
Left no forwarding address so that mail was returned and e-mails disappeared into whatever graveyard file they go to.
For 960 women the mail was returned undeliverable.
Pilot studies showed that address information held by the MoD for discharged personnel was inaccurate (21% pilot mail was returned undelivered).
Despite considerable effort spent on attempts to trace and contact all members of the two cohorts, a sizeable proportion of the subjects did not respond after two reminders to the same address, or their mail was returned undelivered.
Eighty-three wofen of these 184 had left their registered practice and could not be traced, or mail was returned as undelivered mail, moved house or addressee unknown, and 101 women refused to participate for various reasons (e.g. questions too personal or lack of time).
Mailings were sent in envelopes with the study logo requesting that mail be returned if sent to the incorrect address.
Carr, the former tax official, said the breakdowns in the office were so extensive that thousands of pieces of mail were returned each year and never re-sent.
States would be banned from engaging in voter caging, a process in which election officials purge voter rolls by sending out non-forwardable mail and then removing anyone whose mail is returned to sender.
Each year we are notified of more than 10,000 address changes and some mail is returned as undeliverable.
The e-mail was returned as undeliverable.
Also, since the mailers were stamped "Do Not Forward," some Democrats alleged that Republicans were preparing "challenge" lists for every voter whose mailing was returned as undeliverable to the state GOP.
