How much do they read the New Testament???
Their scripture says that the prior scriptures are the word of God, but then it goes on to refute those scriptures, claiming the old scriptures are wrong and the Koran is the most accurate. On top of that it claims to have no contradictions.
My guess is they don't read them very much, if at all.
They argue in circles on this. If the Koran disagrees with the Bible, they say that the Bible has become corrupted at that point. When asked how they know that, they say they know because it's different from the Koran.