Hello, sorry I am late, I just got notice of your question.
Not all installers do it perfectly... the most common mistake is to put just a few extra ounces of refrigerant in the system... that will allow cooling, but not dehumidification.
In humid areas such as Florida, the cooling coil must be run colder than in milder climates, a colder coil draws more moisture out of the air.
Reducing the air flow across the coil can also resolve the issue... that allows the cooling coil to run colder.
Since the company has not been able to solve the problem so far, it is quite likely they have missed these two points. In that case what you hear is 'we installed it to factory specifications'..... that is the artless approach. Every house is different. They have missed these two primary factors in achieving good humidity control.
It is going to take a more skilled set of technicians to put gauges on the system, and determine which is that case... this is generally not a difficult situation to resolve.
Let me know if you want a reference to a local company who can make those adjustments or not, I will need to know which direction you are from the center of the nearest city in that case.