ASUS cashback on Amazon a “scam”?

I have now spent 1 hour on the phone with Amazon customer service and supposedly 1/2 hour with the “boss”.

Asus says Amazon has to give out the promotion code, Amazon knows nothing about a cashback campaign.

So a discount is advertised on the Asus site, which is then not honored. I told the “boss” whether they didn't have a legal department if a company advertises discounts on Amazon that are then not honored. Furthermore, I couldn't imagine being the only Amazon customer in the German-speaking world with a population of around 90 million who would have this problem.

At Mediamarkt (Austria), the cashback worked 1 year ago with my Asus RTX 4070.

Does anyone have any experience with Asus cashback and Amazon?