When pointing out the actual teachings of Christianity to a sceptic who has misrepresented it, it is very common for that sceptic to say something like "you mean your version of Christianity". It is erroneously claimed that there are many versions of Christianity, and even many interpretations of the Bible.
The first problem with this is that it's ridiculous to say that there are multiple interpretations of the entire Bible. What they should say is that there are multiple interpretations of specific verses, or passages. Most denominational differences are actually quite trivial, making some very petty disputes, such as whether or not infants should be baptised, or what leadership roles should exist in a congregation (and who should be qualified to fill them).
There are bigger disputes, of course, which brings us to the second problem: They're not all valid. More often than not, differences in interpretation are either due to a lack of education (I guarantee you, not every nominal Christian you meet has read their Bible), or it is deliberate. But if you have ever read anything, be it a religious book, an instruction manual, or even a children's story book, you know that some interpretations are more valid than others, and some are flat out wrong.
In fact, ironically, religious texts are the only ones where basic rules of language are thrown out the window. The Bible says what it says, means what it means, and any literate person with access to a good translation (or better yet, knowledge of the original languages and access to them) will be able to understand that, and, barring some kind of bias, all of them will come to similar conclusions. And they do. As I said, most Christians disagree on only the smallest of things.
But now let's get to the most ironic part of this argument. If you want to say there are so many versions of Christianity, and they're all lumped together into one faith, you're actually making it impossible to refute Christianity.
See, when you discuss Christianity with me, you're not arguing against, for example, the Pope's idea of Christianity, you're arguing against mine. You can say his religion is wrong without touching mine, but the second you lump us both together and call that Christianity, you actually can't say Christianity is wrong, because you don't know what Christianity is in order to call it wrong.
It's also a very strong testimony in favor of "my version" of Christianity (which, of course, can be found in the Bible). If you cannot refute "my version" of Christianity without adding all the crazy stuff I don't believe with it, what does that say? It says that once you remove all the crazy stuff I don't believe, I have a pretty solid case. You have to add the crazy stuff to Christianity because there is no crazy stuff in Christianity. Your strongest arguments against Christianity are not arguments against Christianity! So what are you waiting for? Believe in the Risen Lord, repent, and be baptised!