National Car Rentals do not respond to e-mails

Booked and paid for a car through National's U.K. website for one week's use in the USA. On arrival expected only to have to pay locally for the GPS and local taxes. Was told that my insurance cover was lacking and strongly implied that I should pay for "LDW". This amounted to $182. On return to the U.K. I see from the terms & conditions that "all inclusive rates include CDW", so on the face of it, it appeared that I had paid twice for this element. web searches indicate that LDW and CDW are one and the same.

I therefore, twice, queried this (with full details) through National's "Contact Us" page, but never received any reply (not even an acknowledgement). Calling their premium rate "Customer Services" number only puts you in a queue, and the auto message recommends that I e-mail "[email protected]", which I have now done, but with not much hope of satisfaction. I may have to seek credit card recharge to see if that illicits a response.