Sally Bruckheimer <sallybruc@...>
"I have been trying to contact the Suwalk-Lomza Interest Group to join and purchase copies of the publication of their journal the Landsmen,
to learn more about my great-grandparents who emigrated from the Suwalki region in 1876 to Detroit, Michigan."
The SIG no longer active and doesn't publish the Landsmen journal any more. I don't know what has happened or who (if anyone) is looking at letters. Since they didn't cash your check, I would recommend stopping payment on it, and, perhaps sending a message to the SIG that you are still interest.
There have never been digital copies as far as I know.
I'm sorry that it has come to this, as it was a valuable group, but check on JRI-Poland.org, as much of the information is there as well. Jewishgen.org also has some.