I only sent emails, alternating between the direct email to H. Oswald (who also had been in contact with me) and the form on their website. Didn't always get a reply though, some email got mysteriously "lost" (as did a number of those they said they had sent to my institution, so I had to check every time with my contact there that she had indeed received what they claimed they had sent...).
I think that's where a thread like this one is really useful, because it gives us a feeling of what a "reasonable" timeline should be like. I think 1 month after they claim to have started your assessment, you are well within your rights to constantly harass them by any means possible! Good luck!
