The most common and most likely answer to this crossword clue is the 8 plus 7 letter word CHECKOUT COUNTER
I've seen this crossword clue in The Times
C
H
E
C
K
O
U
T
C
O
U
N
T
E
R
Buddy explains!

The straight part
We know that "bill-paying situation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bill-paying situation = checkout counter.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.