Normally cause by compressor leak or the cooling coil leakage, the most common problem. Just get a sifu check it....cooling coil will cost u around RM300+, and compressor might cost u more, depending on the type of compressor u use...

I had the same problem, add gas, after 1-2 months not cold ady, so I changed mine, a toyota corolla, RM350 for cooling coil. Then jalan few months not cold again, so another leakage at the compressor, so go kedai potong find a good one....cost me Rm380 including workmanship...now cold like fridge! LOL...

Goodluck