like the Nigerian transfer scam, or some variation thereof, these calls keep coming because someone is dazed enough to believe it, the scammer just doesn't know which one. so they keep going until fish on. if nobody ever fell for it, they'd be doing other nefarious things, like running for public office.
Hint: if you have elderly in your family, look at the call records on their phone. more than one call from the same unrecognized area code is an indication trouble has been at your doorstep. We had to take mom's cell away. these people are well practiced at sniffing out an ill-gotten gain a mile away.
Thanks for the great advice. Yeds, these are becoming more and more common. I would change my cell number, except they would eventually call the new one. Sad that are economy is not doing well and these are the new types of businesses that are being created instead of legitimate ones.