The most common and most likely answer to this crossword clue is the 3 plus 3 plus 4 letter word OFF THE HOOK
I've seen this crossword clue in The Daily Telegraph
O
F
F
T
H
E
H
O
O
K
More clues leading to the result OFF THE HOOK
Buddy explains!
The straight part
We know that "Out of trouble/unable to receive calls" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case out of trouble/unable to receive calls = off the hook.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.