BestBuy refused to change my iPhone 7 battery. What now?

So I decided, with my battery capacity at 87%, to take advantage of the $29 battery replacement offer from Apple. I tried to schedule an appointment at my local Apple Store for a Saturday when I was free, but there were no openings for several days. So I got an appointment at Best Buy. I have read on numerous sites that Apple was allowing people to buy new batteries even when their phones had peak capacities over 80%, but Best Buy refused to change my battery. They said that they were not allowed to break that under 80% rule. I tried explaining that Apple itself is authorizing replacements for anyone who wants to have it done, and that I understood that it would not be covered by AppleCare, but the guy still said no. Do I have any recourse? Am I wrong about Apple's offer to replace ANY battery at a customer's request? Are Apple Authorized Repair Centers held to a different standard than Apple Stores? I was pretty annoyed, as I took a couple hours out of a busy schedule to have this done, and now I am not sure, even if I was right and can still get a new battery, if I can get it done before December 31, when the offer expires. Any thoughts?