@matigo The compressor of the AC unit didn’t start up, so they were investigating the reason for that. The first guess was the system had run out of some liquid, which would explain why the compressor does not turn on to protect itself.
Turned out that some cell in the overall cooling system was leaking, so they had to replace that. After the replacement was installed and refilled, turned out that while the compressor gets electricity, so the whole compressor unit was busted. Another replacement to be done. And that was the wrong part they received and caused the delay.