The importer of record is responsible for paying duty. The seller of the goods cannot pay duty in advance. Be leery of sellers who claim duty on your purchase will be prepaid. Cleared and Delivered may pay duty on your behalf as part of their services in clearing your goods when they arrive in the United States.
Customs Clearance-Government Agencies
For a seamless customs clearance process, consider using Freightclear, a digital customs brokerage service that simplifies shipping, clearing, and delivery of imports to the USA in