The contact phone number , with time slot on Wednesdays, is given at the following URL:-
(but as mentioned, they did not answer the phone during that time).
In addition to Bialystok, Narewka, Bielsk, I have some of my paternal ancestries from Lomza, Lodz, Warsaw and Bransk. Also, possibly Brest (Brisk) now Belarus.
Ma'aleh Adumim, Israel