I paid a local car stereo company to install backup alarms in both my cars. The charged me $535 but the units did not work at all since I suspect they were not installed correctly. The company offered to install another simpler set of alarms and I agreed. When I asked to be credited for the difference in price between the units, they refused. I found that the second units sold for $42 each on the manufacturers website. They have mentioned "Theft of Services", since I disputed the charge on my credit card to try to get them to be fair with me.