For the delivery failed packages ShipAnt could help you arrange re-delivery once the forwarder warehouse in eu usa received them, if clients want to refund due to quality issue or unlike as well as other issues, you can send them ShipAnt China warehouse address info for they to return since the overseas warehouse service cost is very high.

When clients return packages to China, please make sure ask them ship via post service with lower goods value(usps, roymail, neitherland post, dhl paket etc. each country has post service) instead of business courier service as it might occur tax and custom clearance service fee.