The lady on the other end spoke in a very pleasant voice and asked me for my feedback on paypal. I thought it was a nice gesture on the part of the company to ask me about my opinion since I used paypal for most of my business transaction. I bought a lot of items from Far East countries and sold it in my country and I always preferred to send money to the seller through paypal using my credit card. So one morning when I received a call from a lady stating that she was calling from paypal I was a bit surprised. She later told me that there were some illegal transactions done on paypal using my credit card number and she needed me to tell her the 3 digit security number on my credit card so that she could block the illegal transaction. I immediately suspected that the caller at the other end was a fraud because I had heard about people falling prey to such paypal credit card fraud telephone calls. Sometimes knowledge of such things help you avoid becoming a victim of fraud.