Who sent me a PIN number from P.O Box 24410 in Omaha, Nebraska 68124-0410?

Yesterday my husband received a discrete piece of mail that you usually get a new PIN number for your Debit card, which I actually received one from my bank the same day. It says I have a new PIN number for my Visa OR Mastercard and that my new Visa OR Mastercard has been sent to and should have it in my possession and if not call a 800 number. There is also a number to call if you want to change your PIN. I am thinking this is a scam because there is no Company name anywhere, the only new card I have got was from my bank because I lost mine and canceled it right away, and it says either Visa OR Mastercard. Who else has gotten one of these and what did you do about it.