The only thing that you can do is follow a logical procedure here.

If the windows go down, it means the sensor in the windshield frame is fine. The next items to check are the sensor in the trunk for the divider and the "top open" switch on the passenger side of the top - these two are wired in series and both are known to act up. The two of them must close to apply the ground to the Top Control Module.

If those are ok, then the "trunk closed" sensor has to indicate that the trunk is closed. Now, as you press the button, you should faintly hear the electric lock activate, locking the trunk lid closed (for the 23 seconds the top is moving). When the button is pressed, can you hear the latch in the trunk move? It is a faint sound... if no sound, that points right back to either the two switches I mentioned, or there is indicatoin the trunk is not closed.

Anyway, if you are not in possession of the car, I can't help you.

Id' suggest you cut a deal with them - you don't pay, and you agree to take the car back as-is. THEN, we can help you get this fixed. If it works once in a while, it is NOT a bad hydraulic pump or blown up control module - it is a switch or sensor that is loose, broken, corroded or acting up.