Why make a booking

I normally do not report on bad service, but this pushed me over the edge. I made a booking with A and J AutoWorld way in advance for the installation of my new car radio and speakers. The booking was accepted and I was told to please be there early. I arrived before 8 in the morning and waited for them to open. I then took my radio and speakers inside to reception and filled in the customer information slip. I was then told that they were fully booked with major installations and that they would not be able to assist me. I stated and confirmed with the reception lady with regards to my booking. the owner still said we can not assist you. This all happened in front of other customers. I will not recommend them to anybody. I will also inform Nissan with regards to this poor service as they referred me previously to them. In an economy where money is tight A and J Autoworld should rethink their approach to there customers. :(