Radco Refrigeration and Appliance service call charged more than what quoted Spring Hill, Florida

I thought my air conditioning unit may need just a routine maintainence, for it was taking longer for the house to cool down during the hot part of the day, thought maybe low on freon.  I called Radco on a Saturday, since they advertise 24-7, and spoke with the person who answers the phone,  I lined up an appointment for them to come out and check the unit to see if needs freon etc.  I did not schedule for that day since it was not an emergency,  I scheduled for Tuesday and was told it was $69.00 for them to come out and I would receive a 10% discount on that also.  well they came out Tuesday, looked at my unit, told me that it would be $550.00 to clean two coils and adjust the pressure. I looked at the man. he told me if that did not work then the money would be applied to a new unit which would cost me $5,500.00.  I told him I would have to wait.  He charged me $79.95 for the visit though I told him I was told it was $69.00 quoted on the phone, and he told me I would only get a discount if I started the service today, that the discount did not apply for coming out.  I was not told that either.  their add in the yellow pages even shows a tune up special for $23.95, no expiration date which includes a complete inspection of cooling system, oiling motors, check freon level, 1st lb freon free if needed with leak repair.  I did not get any of that and was charged $79.95.  He checked the pressure only and summed everything from that.