Air Conditioning problem
1996 Honda Accord 4 cyl Front Wheel Drive Automatic 293000 miles

i am not happy at all my AC is giving me hell lot of problem this year i have spent close to 300 USD to fix it but nothing seems to working
recently i was asked to change the expansion valve which i did but the problem still persist.
yesterday after d technicians finish their work on it and refilled d system i noticed the refrigerant was coming out from the vent and everywhere in the car was smoky that is the 2nd time is happening and today no more refrigerant in the system \
what can posibly be the problem
i am very sure that there is no leakage from outside i maen inside the bonet
pls help me out