teguh123, take a deep breath. What you have described, (not completely coherently, but sufficiently well that those of us who do know history can recognize it), is the belief of a number of people who do not know history that Christianity was “created” (or “manufactured”), at Nicaea, including the creation of the New Testament. This claim is in error.
It is true that we cannot know every letter or essay written between 33 C.E. and 400 C.E. It is also true that some texts were probably suppressed, either then or later. However, the point that people who advance your beliefs seem to miss, (over and over again), is that the groups among the Christians who eventually “won” the battle to decide what Christianity “really” meant spent a lot of time and effort criticizing the people who eventually “lost” those battles. Even if we do not have the original works of kooks like Marcion, we have a number of texts written to criticize Marcion and describing his works. Similarly, the Muratorian Canon that identifies most of the books in the current New Testament–including the current four gospels–appears to have been written around 170. We then have letters and essays discussing books that should be included or excluded over the next couple of hundred years. Why would we have some texts delberately talking about the exclusion of the Shepherd of Hermas while some other text that described omitting some other book was suppressed?
The notion that we are completely unaware of all the changes to the scriptural canon or to Christian beliefs prior to 325 are simply without foundation. We may have missed a point here or there, but the basic history is well documented. (Note, also, that at Nicaea, not one book was included or excluded from the canon. The council simply declared that the existing books would be canonical.)