I have heard that a Jewish convert who does not keep Shabbat loses his Jewish title - is this true? Our community is an Orthodox community and we hear such rumors and I would like to know the Halacha.

If at the time of the conversion the person did not intend to keep Shabbat, this person never became a Jew and there was never any conversion. If at the time of the conversion the person wanted to keep Shabbat, then this person became a Jew. Rabbi Moshe Klein