I have made an appointment for an alarm to be installed in my Hyundai Venue

I have made an appointment for an alarm to be installed in my Hyundai Venue. After getting a quote 2 days prior. I arrived at 7am on Friday, the day of the scheduled appointment, as also confirmed via a message from Hyundai, waited in the queue, car was booked in. Only to receive a call 3,5hours later to say that the alarm had to be ordered, i needed to first pay a deposit, and that the part would only arrive on Monday to be fitted on Tuesday. How was this never communicated to me? Not even when I physically went to thr dealership on Monday to enquire about the cost and received the quote? I dont even want to start with how they ignore you while sitting in the reception area. But they can quickly call you to try and sell you a vehicle.