Honda Cars India Ltd. — ac cooling problem every four months in honda city car

I have purchased the new honda city from Lndmark, ahmedabad 8 months before, initial four month AC was working and cooling was god, thereafter I shown to honda service station . He said there may be the leakages problem hence they filled the gas again. After again four months same problem is persist,

Need your help to rectify the problem Permanently..

Because of repeated problem we are fed up..