Whenever you get news like that you should promptly end the call.
Always say "hold on, I'm at work" or "I'm in the middle of something let me call you back in 5 minutes"
Record the call or the call back and start with "what happened?"
You need to get their admission. Business bureau and insurance, even a judge is going to side with the business. If you get their admission and explanation, it's a wrap.
**That's usually why mechanics/contractors don't break news over the phone but in person. If something gets broken, damaged, replaced usually they have to consult with you to talk about repairs, replacements, parts, material. That's not necessarily an over the phone conversation but in person as they point out what's wrong, etc.