my mk 3 mondeo 18 pertol hatch zetec non climate control is leaking on my p?

my mondeo mk 3 1.8 petrol air con has never worked since i had it in 2005, went to kwik fit they said it was empty could be a leak or jus low so they topped it up it worked for a day or 2 then saw water on the pedles the next day now jus blows hot air, ive changed the thermostat and fluid for that hot air in winter works great but no cold air wanna get it done but dont want to get conned please help