This is what I read on the official website.

The Russian Embassy in Bangkok is empowered to issue Russian visas (all types except transit visas) only to foreigners who hold a Thai residence certificate or who have been granted permission to stay in Thailand continuously over 90 days.

We are residing in Thailand since August 2013 and our stay ends in July.(we have a B and O Visa valid till the 31st of July 2015) When I called the Embassy yesterday, I was told that I need to have a visa for Thailand valid for over 90 days.

Mu question to the forum is, do I not fall into the category mentioned above or not?

Since visas don't last for a couple of years, we assume your Non-O and Non-B visas mentioned are new and don't cover your stay from 2013?

How did you stay before, ie. what visas (if any)?

Having a visa does not confer any residence status in Thailand.

After a five hour wait, and a lot of questions asked our applications were accepted. We witnessed how, many were refused and asked to apply in their own country. Our tip is, take items such as work permit and a letter from your landlord to certify that you live at the address. If you are on a tourist visa, do not waste your time in the que. I watched at least five who went empty.