I just had my HVAC fixed maybe 2-3 weeks ago. I had HVAC problems last year as well and it was still under warranty back then. I'm just a tenant there so the landlord fortunately took care of things for me (although it took a while for property management to get the contractor info and get a quote etc). This year, original diagnosis was that the compressor needs to be replaced and the quote was somewhere around $2000 (yes, crazy, could've gotten a brand new A/C??). And then they come again to check again and then decided it was something else... and they flushed the water pipes or something and then it worked.
It was pretty obvious the time that they charge $35.xx per HVAC unit maintenance (filter changing etc), they did not actually do any "maintenance" or even basic checking, most likely just came and change the filters and that was it... (this is just what i thought, but it seems highly unlikely they checked everything was working and then the next week I turned on the AC for the first time of the year that it wasn't working)
No idea why there are so much problems with HVAC with this building....