That does seem shitty. I'm surprised that the site coding allowed the model to adjust the private rate once your request had been sent.Requested a private with a model. She increased the price (I think doubling it) and then quickly accepted before I could cancel the request. Fortunately, the minimum number of minutes was relatively low, so I just typed something like "WTF did you do that for." and closed my browser. I still kick myself for not taking screenshots and reporting her.
However there *may* be some explanation, such as the model had reduced the usual rate for an earlier private, and had forgotten to raise it back again afterwards. I've seen this happen, including the room I'm a moderator in.
But I would hope that if this were the case, the model would decline the request, let the user know why, adjust the rate again and let the user choose if they still wanted a show.