Some of you seem to feel like it isn't a big deal, however I can completely sympathize with the OP. When you buy snakes specifically for breeding and you find out later on that they are sexed incorrectly, especially when you are only a few months away from pairing, it is completely natural that you would be pissed. Some have said that it is good as he got a female for the price of a male, but with spiders the prices are separated by at most $50-$100, and if you have no need for a female spider then you have no need for a female spider! To the OP, I would try probing again or probing the other side and seeing what you get. I hope this turns out well for you but if not maybe you can fit a female spider into your breeding plans.