Ford focus 56 plate a/c not working?

I bought this car and after a few weeks I noticed the a/c wasn't working so the dealer found it was the condenser that needed replacing as refill didn't last and was working brilliantly. through out the winter, the a/c would click on itself and would have to turn it off. With the recent warm weather I went to use the a/c and noticed the air temp wasn't changing so I brought the car to kwik fit for a refill. It worked all the way home and when I used the car the next day it wasn't working again.Kwik fit refilled again but the same thing happened, so they gave me a refund. Does anyone have any ideas what might be the problem. The car is no longer covered by the dealer to go back with this problem.The condenser was replaced just over a year.