St.John of Damascus

I dont understand the statement of ST.John of Damascus, what he claim many of them can't be found in Quran like he say "Mary is sister of Harun and Musa" but nowhere in Quran say it,Quran say she is "daughter of Imran and people claim her to be sister of Harun", again he claim "Muhammad says this, that when the Christ had ascended into heaven God asked Him: ‘O Jesus, didst thou say: “I am the Son of God and God”?’ And Jesus, he says, answered: ‘Be merciful to me, Lord. Thou knowest that I did not say this and that I did not scorn to be thy servant. But sinful men have written that I made this statement, and they have lied about me and have fallen into error.’ And God answered and said to Him: ‘I know that thou didst not say this word.” I also don't find it like this in Quran it’s much different in Quran to check Quran 5:116-119.Again he claim "Mohammed says that the Christ asked God for a table and that it was given Him. For God, he says, said to Him: ‘I have given to thee and thine an incorruptible table" I also dont find in Quran Incorruptible table like something, it was table full of dish of heaven.Again he claim in sura bakara "He made it a law that they be circumcised and the women, too" but there is no verse like this especially the circumcision of women, where the hell he found something like that?And many more thing like she camel of god,did he himself had the faulty view of Muslim somehow by hearing hadith(or some propaganda) with Quran?I dont think Quran had changed as we have a 1st century manuscripts which contain 95% or some say 100%of Quran,if it changed christian's would have announced it to the whole world as they did with sana manuscript. So what exactly the problem?