Air conditioning Barina SB

Hi I have a Holden Barina SB swing year 2000. We have always had great air, Recently it just starting to perform badly. We took it to the repair shop and had the compressor, TX Valve and reciever dryer replaced and regassed. You would expect it to work ok after that. With an outside temperature of 28c the air coming from the cooling vent only gets down to 13c I suspected the heater could be a problem so switched the air off and measured the air temp from the vent after a period of running which was the same as the outside air temp. Any ideas anyone ? Please.