One of my problems in Mexico City has always been trying to set something up over the the phone. My spanish just isn't up to it. So when I found an agency that spoke good English I gave them a try. I have spent lots of time on the phone trying to find someone on past trips.
The agency is Golden Body. Web site is [url]http://www.golden-body.com/[/url].
I have used them twice and been very happy both times with the girl that shows up. Although the face is blanked out, the girl in the picture appears to be the one that shows up.
They have different levels of girl which determines how much you pay. You can check the web site out and see the range of prices. I like the Barbies that start at 1600 pesos for an hour and a half. I know you can find cheaper, but being able to set the whole thing up in English without misunderstandings is worth a lot to me.