Last week I spoke with an optics guy in Russia who has known Sergey for many years. He thinks Sergey must have gone to his country house for vacation under the assumption that the lenses he sent to people must have arrived safely. If that's the case, it could account for his cell phone blocking calls as those rural places tend not to have cell phone reception. Maybe, he shut it off so that those calling would know he wasn't able to receive calls. This is the exact time of year that Russians go to their "dachas". Let's hope.