The airconditioner in my car works its cool through the floor vents and the vents on the dash but no air is coming through the main air vents ? the car is a vs berlina with climate control ?

The blend is not working.

usually a faulty blend door under the dash

Sounds like your heater coolant hose door flap is broken or loose. May want to check behind the heater controls, if your components are mechanically operated. If electronically, may need to perform more troubleshooting before replacing this component.

There is a blend door acuator which moves when u change your settings. Its a electric motor. Down under dash, Will need a mech and a heating and cooling diagram to find where the motor is,

Blend Door Actuator.Should have 2.One will controll the air across the heater core,and the other will adjust air flow direction.

Have your thermostat in your heater core checked sounds like it is stuck, your next clue will be very wet carpeting that smells like coolant.

Check for vacuum hose leak.

The climate control was poorly designed on these cars.

There is only heat on the floor and defrost settings, due to the layout of the ductwork.

Chances are the electronic/digital HVAC control unit is bad. This same problem happened to me and I had to replace the entire unit. The dealer wanted to charge $800 for just the part! After I freaked out on them, they found a used one for less than half. Sorry, but there's no easy fix here.

linkage inside dash or relay for electric front vents went bad
linkage sometimes comes off its holder from usage this is normal there only held in by a upin under the dash
if electric the relay for the the top vents needs replacing this i believe will be with rest of the relays in engine compartment