Anyone that calls your number and they can not be called back is up to no good. Don't answer as call from any number you do not know on your caller id. See if they leave a message and if it can be called back. If either they do not leave a message and/or you can not call them back, just report the call here and forget it. They are up to no good - a scammer.
The callers are the drug-addicted "card services" scammers, who call us, pretending to be associated with our credit card companies, in an attempt to fool us into giving them our credit card numbers, so they can rip us off. People that have given their card numbers to these junkies have suffered severe financial losses. Beware of these lowlifes, and warn others, before they are cheated!
Anyone that calls your number and they can not be called back is up to no good. Don't answer as call from any number you do not know on your caller id. See if they leave a message and if it can be called back. If either they do not leave a message and/or you can not call them back, just report the call here and forget it. They are up to no good - a scammer.