Onida — Onida split AC

I have purchased 1.5 ton Onida split AC in 2012 from DG World(Swift associates) Nerul, Navi Mumbai. Within warranty period, the compressor failed and had to be replaced. While replacing the same the service agency in Kamothe charged me approx Rs 4500. After replacement of the compressor there was inadequate cooling and vibrations with lot of noise. But the agency did not pay any heed. After a few months, gas leaked. Gas was topped up without carrying out any prssure test etc. Within a month and half the gas leaked again and in this period the AC was not used as I was out of station. Now there is no cooling, the agency sends various technicians for inspection, and has till date not attended the issue. Further the agency has told me that there is only one month guarantee of gas refill and I will have to pay Rs 2500 again .The problem is due to incompetent work done by the technician whle replacing the compressor and they make me suffer and pay also.