The seller is responsible for both ensuring hops are delivered to the buyer in good condition and providing proof of delivery. If there is a problem with a shipment (delay, lost or damaged package, or other exception), it is the responsibility of the seller to work with the shipper (UPS,  FedEx, or LTL carrier) to resolve it. See resources for filing a claim with UPS or FedEx below. 

Buyers are eligible for a full refund for damaged or undelivered hops.

Relevant links for sellers:

UPS lost package claims process

UPS claims/damages/losses FAQ

FedEx EClaims

FedEx claims support