First I would contact the Retailer you bought it from. They would be where to start as maybe they can exchange the product for you. If not I would contact AMD under warranty and explain. You are far from the first to complain about this. Next if they can't help, contact Cooler Master maybe they will as they make the coolers for AMD or hopefully at worst can sell you one.
Contact AMD warranty here: https://www.amd.com/en/support/kb/warranty-information/rma-form
You can also contact AMD support and ask if the RMA form goes nowhere: https://www.amd.com/en/support/contact-email-form