You may need some experienced technician/air-cond installer that troubleshot the problem, as air-cond function is quite simple. Some installer may be more professional in installation but poor in troubleshooting. 

If not cold, generally only a number of issue.
1. Capacitor faulty that lead the compressor not working (fan at compressor may be spinning, but compressor is not).

2. Sensor faulty, which lead to compressor taught the room is cool enough, don't need to work

3. PCB faulty, which lead to compressor fail to function properly especially for inverter.

4. Gas leaking

5. Compressor KO already.

To add:
Above issues, you have totally warm air, and the air-cond works like ordinary fan only.

If the air-cond is still blowing cool air, but not cool enough, then it is another aspect problem to look at.

Better use coway's aircon, it's inverter type, save energy and they have free care services for 5 years. You don't have to worry and ask someone to repair with expensive charges.

sorry to revive a old thread, but have a 1 yo Panasonic 2.5hp aircond with this problem.

at first have F95 error code (Panasonic), installer came to take a look tried to wash indoor and outdoor but same error. So gave quotation to change motherboard and fan motor which we did.

today is day 1 of the new motherboard + compressor fan motor but it's Cool air but not "freezing". Even after 2h of 17c set, room still feel "normal" ie no need blanket.