The most common and most likely answer to this crossword clue is the 7 letter word UNHEARD
I've seen this crossword clue in The Daily Telegraph
U
N
H
E
A
R
D
More clues leading to the result UNHEARD
Buddy explains!

The straight part
We know that "is not listened to" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case is not listened to = unheard.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does UNHEARD mean?
UNHEARD adjective- Not heard.
- Not listened to.
- Not known to fame; not illustrious or celebrated; obscure.
- To reverse the process of hearing, so that (a sound, etc.) was never heard.