Charging for more volume than actual

[Globltrekr]

I thought this would be a common scam but I could not find a post. This relates to an international shipment of household goods from Germany to the U.S. My wife and I shipped about 47 boxes that I personally packed. There are a few misc-shaped items but most were 2.3 CF boxes. I calculated the shipment to be 105 CF. The shipper picked up the boxes. At the time of shipping to the U.S., they gave me a new number of 210 CF. I know that is not possible and I argued with them. They told me they would remeasure the shipment and make any adjustments. I have a detailed manifest of the boxes, their contents, and sizes. The shipment is scheduled to arrive around the 10th of July. What can I do or is there someone I can threaten to report them to if they insist on the size of the shipment?