When a seller uses USPS to send a parcel why is it that the eBay hub transfers the parcels to DHL, gmbh whom add cost on what has already been paid for.

When a seller uses USPS to send a parcel why is it that eBay hub transfers the parcel to DHL, gmbh? | Buying

When a seller uses USPS to send a parcel why is it that eBay hub transfers the parcel to DHL, gmbh? | Buying | eBay Canada EN