It's not uncommon for a customer to come at you with a statement or accusatory question that will send your body into fight or flight mode.
What do I do to help them? I'm not sure what they're upsetting about!!
What should you do? Ask clarifying questions.
"This is a big deal I'm so sorry. Were you upset over the quality or the price?"
"I'm not sure if you meant you don't like the colour or colours in general, can you share with me more specifically how you feel?"
You ask because you care, but you also ask because you need to truly understand to fully resolve an issue. Don't let your brain go in a million directions wondering what they're thinking, ask and you will most likely get better information and often see that an issue is much more solvable.