Rav Shach made a public statement about Chabad followers calling their Rebbe the Mashiah. Rav Shach said on Youtube that one may not trust their shchita or send children to learn at their yeshivas,cheders follow their customs etc. Is it true? As a baal teshuva I bought my tefillin from Chabad and mezuzot etc. I now try to follow RAV Elieshev understanding of Torah but living in community with no Jews and being disabled there are challenges and no one to ask for Halacha help. In a litigation society you may be afraid to answer my question. Torah is the truth. One must fear Hashem only.
Although Rav Shach did attach Chabad Chassidus, this was because he felt that Lubavitch messianic belief was a danger to the general Orthodox community, which brought him to make some very harsh statements.
Yet, there is no halachic problem with Chabad Tefillin (they will be written in the Arizal script), and of course Chabad Hassidim are meticulous about mitzvos.
The rift with Chabad has softened over the years, and there is no need to bring it up in a halachic context. Rav Elyashiv did not give the issue attention, to my knowledge.