Looking for negative traits this one. But remember even though you cant always get someone to see your point of view be self reflective on yourself and what you could have done differently to get a positive result. Normally for CBI the answers are STAR(Situation, Task, Action, and Result), but in this case add an alternative result that demonstrates that you have thought about it, but dont hold grudges.
the answer is that the customer service on the calls is perfectly polite but is hardly exceptional. Customer should expect the best customer service to resolve any queries, and if the recipient of the call doesn't know the answer then he/she should offer to pass it to another department to provide more detailed assistance.