2 days ago, I noticed that the AC was not cooling my condo unit properly despite the cool setting being on and the desired temperature being set well below the room temp. With the heatwave in Toronto, the temperature in my unit got up to 27-28 degrees C! The vents are blowing air but it's not very cool and it's still really humid in here.

The AC unit is flashing 15 times, which according to the flash code means that there is an issue with the "Condensate Overflow Switch-Compressor Lockout." According to my layman's research, there is a draining issue in the condensate or main drain? 

This makes sense because when I turned the unit back on after 12 hours, it started working for a few hours before having the same issue. I think the condensate overflow switch is draining really slow so it can't keep up with normal use.  

The AC unit model is VSCS18C1. I opened up the panel to see if I can find the pipe or drain plate to clean but I can't access anything. 

Building management is saying that I need to call a contractor but will they be able to clear the central drains too? I get if the blockage is in my individual unit but if the main drain is clogged, isn't this considered a common element and therefore the condo corp's responsibility? I'm worried I will pay $$ to clear my unit drains but the issue will come back because the main drain wasn't cleaned.  

How much do you think it may cost to fix this in Toronto? I'm dying in this heat :( thank you so much in advance.

AC is blowing air but not cooling