Called me and I foolishly gave them info on my card, then called my card company to stop my card and issue another, just had a feeling that they were not on the level. Then discovered all these comments, glad I stopped my card!!
I usually ignore phone numbers I don't recognize, but since I was expecting an important call to help me clear up a hospital bill, I took the phone number. As soon as I heard an automated speaker saying that they were from "cardholder services" and that there was "no problems with my account" and that "it was urgent that I called back," I hung up.