Some one (from 9136946558) called me and said they are calling from SBI Credit Card Services, Nungambakkam, Chennai. They told me that my credit card is going to be upgraded and the existing one will be inactivated in few minutes. Then they called me from the same number after 30 mins, and asked me whether i want to redeem my reward points and asked my details. As i was believing that they are calling from SBI Credit Card services and accepted. I don’t know the reality behind it.