Rebate Card

I upgraded my xfinity  mobile phone and was told I would get a $400.00 rebate card. That was in August of 2019. It has now been 21 weeks and I still have no rebate card and the online system says that it is being validated, which it has said for 21 weeks. I call the Customer service number and I am on hold for now 49 minutes without any answer. What is going on?