This crap has happened to me several times. In every case as soon as you agreed to the new price, they raised it again. They're just trying to squeeze more money out of you, because you didn't haggle. A lot of people I know would try this if you just took the offered price. They assume because you just jumped on it, they must not have asked for enough. I learned the hard way, once this starts, you might as well just walk away.
