The most common and most likely answer to this crossword clue is the 4 letter word SORB
I've seen this crossword clue in Financial Times
S
O
R
B
Buddy explains!

The straight part
We know that "service" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case service = sorb.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 SORB mean?
SORB noun- The service tree, Sorbus domestica.
- Any of various related trees, including the wild service tree, S. torminalis, and the rowan, S. aucuparia.
- The fruit of any of these trees, especially of the service tree.
- To absorb or adsorb.