Transferred from Verizon, was promised my phones would be paid off

Hi,

I recently transferred my plan from Verizon over to Xfinity because of their promotion that they offered me while I was on a call about getting a better rate for my internet service. Long story short, I got talked into switching over to Xfinity. I was promised they would pay off the rest of the balance of both of my phones if I switched and signed up for their unlimited plan, but just a few days ago I got a bill from Verizon for $1,337.15 which is the remaining amount I owed on both of the phones I transferred over. After calling customer support, they promised me that I would be receiving a "gift card" via email. I have never heard of this before, why would they not just pay Verizon directly? Why do I have to recieve some type of "gift card" in an email? This seems like your typical Indian/Nigerian prince scam. Can someone please explain to me what this is all about, and why I am being offered a gift card instead of an account credit/direct payment to Verizon? My bank account was personally charged the $1,337.15 which was a huge hit for me. Please can someone tell me if this is normal for Xfinity to promise a gift card to someone for such a high amount of money?

Thank you,

[Edited- Personally Identifiable Information]