http://www.readymix.com.mx/
I've had two deliveries from these guys who are located near Ixtlahuacan.
We didn't hire a pump so we had to have six wheelbarrows with six guys hauling the mix to where it was needed. They give you about an hour to unload the truck which was 12 cubic meters last time.
Recommend buying a large sheet of plastic for where the transfer happens, there will be spillage.