thesmartshoppersavings keeps calling trying to sell! Internet

earlyer today i get a call on my cell phone, i see its a different area code so i dont answer they did not leave a voice mail then they called back about 5 min. later again not leaving a voice mail. a couple hours later they call again now im wondering who this is so i answer and its this lady who barely speaks English and shes talking so fast i barely understand or catch what shes saying, then i hear they have a $100 target gift card for me.
immediately i smell somethings fishy so i asked her how did you get my number and she keeps mentioning the smart shopper savings name no im not interested and the lady tells me ok thank you.
30 minutes later same number is calling me! i answer this guy barely speaking English immediately tells me he has a $100 gift card for me i dont have to purchase anything and for security purposes he was gonna start recording our convo! ok i know they record when they need some kind of a verbal agreement! so i say ok(lets hear it).
as hes rambling he says something about paying for shipping and handling$6.. and after 5 days on a program at$6.. i stopped him and told him not interested, he tells me my email address.. i said i cant trust you, and not interested  in anything i gotta buy because i dont have a credit card.. (wait for it).. HE TELLS ME I SEE U HAVE A VISA!! now im freaking out! i ask him how do you know i have a credit card? he said they are a multi bilion dollar company and they have all my info. after he put my name in the computer..  then tells me to confirm my address! i tell him im not interested im not buying anything and hung up.
while typing this GUESS WHAT?! the number called AGAIN! i awnserd saying IM NOT INTERESTED STOP CALLING! and hung up..
now im wondering if they have my credit card info and everything what stops them from charging it? and can anyone just get your info as easy as they did? i dont even know how they got my name in the first place!