I recently got a voicemail that went something like this:
This is Dr. (name withheld to protect him) from Stockton, California (actual city).
I bought one of your stethoscopes 3 years ago, and I just opened it for the first time last month. It's not working. This thing is a piece of garbage. Your company practices false advertising. I'm really pissed off. Please call me. Well, actually, I'm going to see what I can do to sue your company for false advertising. I'm really pissed off about this.
I called him and his message said he was on lunch. I could page him if it's a medical emergency. I paged him. He didn't call back.
I really enjoy talking to people who use our stethoscope. Very occasionally, a person is having a bad day, and they just need a recharge - fresh batteries so to speak.
I'l keep you posted if I hear back.
Postscript - I didn't hear back. Hopefully he realized that he needed new batteries.