Unfortunately, all my efforts over the last 10 days regarding the need to issue the purchase invoice in accordance with European Union regulations have been in vain. When I finally believed you had understood that the Incoterms DAP rule must be stated on the sales invoice, you sent me an invoice with the Incoterms DDU rule instead, which is something completely different!!! As a result, DHL has proceeded to return the parcel to you. Your approach is frustrating, and despite writing to you countl