Call them and tell them. Make sure you can quote the statute that shows this or tell them that your "contact at the DMV" said if they have any questions, call the DMV. They respond well to specific statutes, especially if you provide them a link to the states website where it can be seen by them.
They have been doing this for years. They are lazy and got in over their heads with this contract regarding vehicles and taxing, titling, etc.. When I bought a truck in MD, I complained and told them that vehicles were exempt from sales tax in MD. They told me that they were required to charge tax on everything they sell, but I could apply for a refund through the state. So, I told them where they could find the proof that motor vehicles are exempt from sales tax in the MD code and that I expected a refund, because they broke the law. They backed down and refunded the tax and told me "The people at the sites are listing the vehicles with the wrong tax code, so our system doesn't know they aren't taxed when it is processed." They also told me that they would make sure they fixed this. I have yet to buy another vehicle in MD, but I doubt they have fixed it.
They also have charged (and refunded under pressure from me) taxes on every vehicle and trailer purchase I have made in PA (over the course of years), since PA does not charge non-residents tax on motor vehicles (to include trailers). They haven't "fixed" that flaw yet, so I get to call them every time and remind them that I pay those taxes in MD.
They suck, but they can be "shown the light". Especially when they are breaking the law...
