The Old Believer/Ritual movement was a reaction to the liturgical reforms of Patriarch Nikon of Moscow in the mid-17th century. There are wide variations between Old Believer groups and their specific views on ecclesiology, but what unites them all is their practice of the 'Old ritual' (use of the lestovka, slavonic version of the creed, two finger sign of the cross, etc.) Old Calenderists also differ amongst themselves and are only unified on one particular issue. They are exactly the same as mainstream Eastern Orthodox Christianity in terms of theology and liturgical practice, the only difference is that Old Calendarists reject the Revised Julian Calendar (which brought the old Byzantine Julian liturgical calendar into accordance with the Gregorian church calendar of the Roman Catholic Church.) This was instituted by Patriarch Meletius IV of Constantinople and the so-called 'Pan-Orthodox Council' in 1923. Because this was done for the purpose of ecumenism and because the Ecumenical Patriarch does not have the canonical authority to make such a change, numerous bishops of the Greek Church (both in Greece and amongst the Greek diaspora,) as well as many other national Churches, separated themselves from the canonical Church and were declared 'schismatic.' Although the Old Believers and the Old Calendarists rarely interact and mostly view each other in the same way as they view the mainstream Church, they have some crossover (search "the jurisdictions of Metropolitan Damascene of the catacomb church of Moscow and Archbishop Auxentios of Athens" for more on that.)

Nope, he found the True Church. Yours is just a schismatic and heretical collection of sects

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Using this logic, the churches that were exiled by God on the day of Pentecost for rejecting the procession of the Holy Spirit

As far as I know there are two Mass locations run by the SSPX. One of them is in Moscow (if I'm not mistaken it's in a church inside the Vvedenskoye Cemetery) and the other one is in Saint Petersburg. Actually, only recently, a Russian Priest was ordained and is now working on the apostolate in Russia.