Scammers!
they called and said they were Publishers Clearing House and asked if I had credit cards.

This number call my cellphone and has been calling for week and does not leave an message.

these people call me two or three times a day, ask if I am 21 and when I say no, they hang up on me without explanation.

This phone number just called me saying they were Publishers clearing house and I was told they were sponserd by the major CC companies. They asked if I have any CC's and I said maybe, then when he tried telling me about the awesome prizes I can get I told him I really didn't want any prizes. So he got all ruse on me and hung up. I called back a lot of times and got a hold of him. (same guy who called) and asked for my phone number not to be called again.