Agreed. CircleCI has had one chargeback ever. It was $19 and by a long-term customer who didn't do a chargeback for any other month. We assumed it was an accident, but didn't contest it (not worth it).
I think it looked like an accounting department had made the chargeback, which implied an accident. It could have been a hidden problem but it didn't strike us as the highest priority one (we've plenty of problems people are telling us about that go higher in the queue :))
It could help identify some hidden problem and as a bonus make them cancel that chargeback.