It is not AMD fault that you purchased a qualifying AMD Processor without first finding out when the AMD Game Bundle became effective. That was your fault for not asking the Retailer if the game bundle came with your purchase.
The AMD Ryzen Equipped to Win Game Bundles starts 09/30/2019 and ends on 12/31/2019.
You do seem to qualify for the AMD Radeon & Ryzen with Xbox Game Pass for PC - Component and System Integrator Campaign which starts on 07/01/2019 @ 9:00AM and ends on 03/10/2020.
Here is AMD's Terms & Conditions for that promotion:
If the Retailer where you purchased the Ryzen Processor is part of the Promotion, They are the one that needs to give you the coupon to redeem at AMD Reward website.
You can open a AMD REWARDS SUPPORT Ticket and see if your Retailer is eligible for the AMD Campaign and what can be done if they didn't give you a coupon to redeem at AMD Reward website.
Here is where you can open a AMD REWARDS SUPPORT Ticket: Support - AMD Rewards
NOTE: I have attached the above Terms & Conditions for the XBOX Campaign to this post. In case you are interested in reading it and want to try and get the XBOX promotion.