Im not sure what answer you are seeking but from what i can see you are obliged to take the car back to the same dealer/mechanic for repairs, if its not repaired properly then take it back again, im sure he will do the job correctly EVENTUALLYas it costs the dealer to have the mechanic constantly repair the car, as for the aircon then consumer affairs will be your next call if the dealer refuses to fix it, get the refusal in writing if you can along with warranty details etc and present the original documents to consumer affairs
if this doesnt answer your question then someone else may have to step in