When you use FBA, your listings are displayed with the Fulfillment by Amazon logo, so customers know that packing, delivery, customer service, and returns are all handled by Amazon.
Amazon’s world-class customer service team manages customer inquiries, refunds, and returns for your FBA orders. This service is provided at no charge to you with the exception of the Returns Processing Fee for certain product categories. When you use FBA, your time can be spent growing your business (or taking a vacation) rather than managing customer service.
For orders from the Amazon.com website that Amazon fulfills, Amazon will manage all customer service associated with fulfillment of your products in the program. Their online returns center provides customers with help pages and details about how to contact them. If the customer wants to return a product, Amazon will direct them to their online Returns Center.