Double Billing

After making a cash payment for VAT/Duties since they were too *********** to link a shipment to my business account, DHL now also billed my account for VAT/Duties and therefore double billed me. I've been trying for a month to get this issue sorted out - their customer service is non-existent. This one shipment has taken hours of my time with DHL - please rather use one of the other courier companies if you value your time.