what the

Half a ring and then nothing.  Most likely some scam artist or telemarketers.  Don't pay any attention to it.

Same as others. Half a ring and doesn't leave a message.

Rang 1 and a half times. No message. I called back. The lady sounded like she was speaking from a train station, busy background noise. The story is that I won a $100 gift card, and she wants my name to verify. I ask Qs first, but she wants my name 1st. I give her my last name and eventually says that yes, I did win and it will require a $3 activation fee. She immediately asks if i'll be using a Visa or MasterCard. Whoa, lady! I tell her that I'm not interested and she thanks me and hangs up. If I had one of those grocery store visa cards, I would have done this but my MAIN credit card?  Don't think so.

So you're the reason why these people keep doing this then? Because you would have happily given them money if only you had a temporary card on you?