Have never received autopay/e-bill credit

Hi, I'm getting ready to upgrade to the 1.2 GB service and I learned about an autopay + e-statement credit. We've been Comcast/xfinity customers for over 10 years and I don't recall ever getting a credit. I've read the credit is now $5 and last year had been $10. Can someone help me with this? We use an AMEX credit card to pay. I found a reddit post about this:

https://www.reddit.com/r/Comcast_Xfinity/comments/18p4mnf/long_time_customer_whos_never_received_an_autopay/