On Us with AirPods promotion & rebates

I'm having issues getting a rebate from T-mobile on the AirPod Promotion.  When I go into the rebate site https://promotions.t-mobile.com/ my phone number is auto-populated and then it requires Promotion Code.  I've never received a promotion code. What is this promotion code and is it unique to my purchase. I have called customer service and they basically seem like they don't know what I'm talking about.  This is quite frustrating and I'd like to get my rebate visa.