We have thousands of New Testment manuscripts dating back as far as the 2nd century, and not one mentions reincarnation anywhere.
Who is "we"? Lol... the Catholic Church? Sorry, but that simply isn't true.
Yes, it simply is true. You are entitled to your own opinion, but not your own facts. "We" refers to the entire scholarly community. There are almost 6,000 manuscripts or parts of manuscripts of the NT in existence today. The oldest of these is currently the Rylands fragment, a portion of the Gospel of John dating back to about 125 A.D., only 30 years or so after the original was written (see http://carm.org/manuscript-evidence). Some of the manuscripts, to be sure, are held by the Catholic Church, others are in the possession of museums and universities. Most are available for scholarly study. None carries any explicit message endorsing reincarnation.
The New Testament is the most reliable of any document of ancient times in terms of the manuscript evidence for the text. Copies of the NT writings were circulated far and wide, even during the first century. It would have been impossible, even then, to have gathered up all the manuscripts and "changed the Bible" - how much more so 500 years later, when the text had been distributed even further?
We also have the writings of early church Fathers dating back to people who were contemporary with the Apostles, and again, there is no mention of reincarnation.
Sorry again, but that isn't true either.
I stand by my statement. As soontobe pointed out, Origen wrote against reincarnation, not in favor of it. The article you cite doesn't actually provide any quotations from Origen that supposedly advocate reincarnation, but relies on Gnostic sources, and even the quotations from them are not explicit regarding reincarnation. In fact, the Gnostics would have denied reincarnation, since their belief was that the flesh was evil and it was desirable to be freed from the body of flesh, not implanted into a new one after death. Even if you could find an odd Church Father or two who believed in reincarnation - and I don't think you can - that's still a long way from supporting the claim that " At the beginning of the Christian era, reincarnation was one of the pillars of belief." Clearly anyone who held such a belief in the early days of Christianity would have been regarded as a heretic.
Nor does finding a verse or two in the NT that, when taken out of context, might be compatible with the idea of reincarnation, prove your case. If you think text has been removed from the Bible, you need to offer evidence - tell us which manuscripts out of the 6,000 have the missing verses. The articles you have been linking to are long on assertion and very, very short on substantive proof. And make no mistake, in making claims such as this, the burden of proof is on you, not on those who disagree with your assertions.