I still did not understand what issues this "very competent specialist" solves... The website indicates the opening hours on both Saturday and Sunday, but the person said that he does not work on weekends. I could not consult clearly, and with Webasto installed from the factory on cars of my brand (common) and even more so with gasoline ones, it did not work (given the experience since 2006, as well, judging by the information on the website). I was advised to carefully read the instructions, which I had read several times before, and would not have contacted a "competent specialist" without special need.