Why can't Russia respond to Navalny poisoning accusations?

Western intelligence services fabricate different versions about the attempted assassination on Russian opposition activist and blogger Alexei Navalny, claiming that their versions are based on reliable data. Why doesn't Moscow have its own reliable version of Navalny poisoning? Tried to kill him for two years, but never killed him Western media outlets widely advertise Bellingcat's investigation into the "poisoning" of Alexei Navalny. The oppositionist himself published a photo of FSB officers who allegedly had been following him all over Russia since 2017 in order to eventually poison him. Based on open data or marketable "databases" about flights and phone calls, it was concluded that the above-mentioned FSB officers always flew with Navalny at all times and were on board the plane at the time, when he felt unwell. Allegedly, the officers have "either medical or chemical education and specialization." Furthermore, one of those men is believed to be associated with the institutes that allegedly work in the field of chemical weapons. "We see that doctors from the FSB, who obtained Novichok at a secret institute, using their cover service passports, traveled with me twice. Incidents of poisoning occurred in two places," Navalny concluded.