I have a rental home where the dog chewed up AC fins outside. AC is still running. So I am assuming, no major leak yet. I have a couple of questions. If I build a fence around the AC, will 2 feet gap (between fence and AC) be enough? also can you actually repair the fins at all?

I recently had maintenance replace the old unit which wasn't blowing any cold air. The unit they got to replace it is a Comfort Aire model BG 143k with a 13600/14000 btu. We live in an 800 sqft apartment and according to the product's website, this is meant for 750 sqft. It was a brand new unit, right out of the box when it was installed in our living room, where the AC wall sleeve was. When I turn it on, I can feel the cold air coming from it if I stand right infront of the vents. However the cold air cannot be felt anywhere except a few feet from the unit, directly infront of the vent. The unit itself is mounted a foot below the ceiling, and from what I've seen, it doesn't have any air dampers to stop it from pulling in outside air. The issue I'm having is that when the unit is on, the air inside the apartment feels very thick and muggy, and if you are on a stool infront of the unit, you feel cold air, but the rest of the apartment will typically feel hotter than it does outside. And the outside air is a lot easier to breath even when it's 90+ outside with a lot of humidity. I've tried every setting it has to offer, and lately I've kept it on auto for the mode and Auto for the man speed. One thing I've noticed is that the fan is always blowing and the condenser will run for five minutes at most. I'm not looking for this thing to cool the entire apartment, I just want it to cool the living room off. I know it isn't right when I have the ac set to 74, have it running for an hour and a half, step outside in 90 degree weather and feel cooler outside that I do in the apartment. I've had fans set up in the apartment to promote air flow and I still haven't noticed a difference, did I just get a bad AC unit or am I doing something wrong?