Their Conflict with the Qur’an itself
These reports contradict the Qur'an itself. Numerous verses of the Qur'an prove that complete Surahs existed, each distinguished from the other. They were in the hands of the people, even those who were idolaters or the people of the Books. The famous challenge by the Prophet (‘s) to the disbelievers was to produce the like of the Qur'an, the like of ten Surahs or even one Surah. This means that the Surah were there in the public hands.
And in the Qur'an itself, the word "book" has been used in many verses. And also in the famous saying of the Prophet (‘s): "I leave among you two valuable things, the book of Allah and my progeny", there is a clear proof that the Qur'an was then written and compiled, because the word `book' is not used for that which is retained in the memory, nor for scattered writings on the parchments, pieces of papers and bones, except metaphorically. It is not right to construe any word metaphorically unless there is an evidence in its context.
The word `book' denotes existence of a collection and not of scattered scribbles, nor of things which are in the memory but not written.