For some context, the ‘Anti-Corruption Foundation’ of Navalny and Volkov was giving talks for European and US state/human-rights organizations for years. It's actually a bit weird if MPs didn't get Volkov's phone number and other contact info from colleages of other countries.

But then, phone numbers can be spoofed, and if these incidents are done by the state—the FSS follows ACF for a long time now, they probably know quite well who Volkov speaks to.