All you have done is to validate your number to these thieves.  You can expect more calls from them as well as other scammers.

The same thing happened to me today.  I accepted the $200 gift card... they also said I shopped at one of their stores and used a rewards card. I'll see what they send me, I won't use the card... they did say it's usable at Walmart, best buy, and other stores alike. All I gave them was my phone number which she already had and my address but didn't ask for any other information. This number sounds suspicious so I'll take it to get looked at before I do anything with it. If it is a scam I'll send a letter back stating I'll report them to the police for harassment if they continue on... I don't remember the name she told me, but the number comes up as Angela W. Has 22 negative ratings maybe 1 positive rating. I'll update on what happens.

Give them nothing. EVER!