Vanity publishing houses that pose as real publishers just break my heart. There are so many vulnerable people out there who put hours of their effort into writing a book and who just want to see it in print.
They are often flattered and coaxed into thinking they have been genuinely chosen to be published, and all they have to do is to pay for a few things to see their book on the shelves.
Money should always flow to the writer, not away. No genuine publisher or agent will ask for money at any point.
It's not a case of trying again if this happens. Once your book has been published, no other publisher will touch it. Not to mention often vanity publishing houses will take rights to the work which they will never properly use, but will prevent the author from reprinting.