I got the exact same call today from dish loyalty program. However, their professionalism was way too bad.
I found that they were very interested in me calling and giving them the green dot number. What convinced me was their ability to add HBO and STARZ channel to my account. They also knew how much I was paying monthly which is way too personal information. Be very careful and do not fall to their gimmick.
I almost did.
I now called up Dish because, as I said their professionalism was lacking in the way they hounded me for money, and to my surprise dish told me that this is a scam and I should not fall for it. I've to rethink about having dish as my provider.
Review about: Dish Network Account.