Exede Wildblue Carsbad , Ca no service in my area Carlsbad California

I ordered service . They set it up to come out. They came out and install a dish and ran cables. after installed found out did not work. Called to talk to company and they told me that it will not work in my area because there was no coverage . Ask why they did not tell me that before they installed it . They said they told me. Asked why would I order something that was not going to work. canceled service . Now they are  trying to charge me $337.27  for something they should not have installed.They were refered by direct tv.