First, no photos = low credibility. If I had a nickel for every time I've seen someone offer N. alata for sale or trade and what they did in fact have was good old Ventrata, you and I could have coffee somewhere nice together. You did not provide photo documentation, so how were we to know what you were really offering. And gosh - I am so glad you know what you're talking about. Perhaps its a shame that people interact on the web the way they do, but a relatively new member with only 14 posts to his name hasn't yet earned a reputation - either good or bad. People judge every situation based solely on what scant information they have. As I say - if only you'd provided photos as requested.
But never mind that. As you yourself have suggested, you can "save it". The angry retort isn't warranted. Though I suppose we now have a better impression of your temperament, at least. :-)