@justbyfaith
The real issues are at least twofold.
1) Their "christ" is not the Christ of Scripture, but is a created being, brother (literal) of Satan. Consider John 8:24.
2) Their gospel, by their own admission, is "
another testament of Jesus Christ." Consider Galatians 1:8-10, there is no other Gospel.
Also consider Mormons will not own up to their own documented teachings. This is a well known trait of this cult.
Apologia Studios and Cultish are two good sources that witness to Mormons and provide great resources into this false "christian" sect.