Odd, Scott Herkelman himself said in an recent interview, people who got a faulty MBA card from one of the board partners, should contact that partnet directly. So it sound pretty weird that Sapphire is redirecting you to AMD. Nevertheless, there are a two options for you:
- Use the RMA ticket system, it was offline for a few days and I am not sure whether it is back up running or not: https://www.amd.com/en/support/kb/warranty-information/consumer-graphics-sold-by-amd
- Give AMD a call directly, so far I heard very positive feedback, at least from German users who contacted them via phone: https://www.amd.com/en/support/contact-call
Since this is mostly a community help forum, you should contact AMD yourself instead of waiting until an AMD employee spots your posting. Depending on your country it might also be very worth a try contacting your retailer and explain the situation. It might be possible they can assist you faster than anyone else.