I was charged sales tax on my order even though my Amazon Business account is setup for tax exempt purchasing. How do I get refund?

Sales tax may be applied to items purchased from non-Amazon sellers. If your item is sold or fulfilled by Amazon, you can request a tax refund directly from Amazon by calling customer service at (888) 281-3847. If you purchased your item from a 3rd party seller, go directly to Orders, find your order in the list, and click Contact Seller. Please give the seller two business days to respond.