said it was important to call this number back. No details

I took a message the other day - the caller ID showed 801-902-7032 a pleasant sounding woman by the name of Carol was calling. I informed her I needed to get a pen and paper to write her information down. She stated "business" was the nature of the call that she was calling in behalf of Discover Card. The number to call was 800-767-1849. Now, I'm assuming the call is related to collections by the response or actions I saw when I told the homeowner who had called for them. They sort of dismissed the call and wouldn't take the callback number. I was ashamed of their behavior.

Bill called me today and left a voicemail with no details as well.

"Bill" said it was important to call this number back. No details