Can the chair of a conference's panel be reported to the organizing institution? I was recently attending a scientific conference, held online due to COVID restrictions.
I chose a panel that interested me.
The organization behind the conference made the rules clear: 5 minutes per presenter, 20 minutes for the discussant and the remaining minutes for the questions from the audience.
In the panel I attended the chair did not enforce the rules at all. Each presenter took as much time as he/she wanted.
Then the discussant complained about never having been in a conference where there was no time rules. He then asked to be allowed to  skip a few slides himself in order to make up for the loss of time. When the discussant was still arguing about the first paper, the technician from the organization body came in announcing that the session was to be closed in 5 minutes. The discussant then was forced to jump directly to the conclusion, skipping a lot of the slides he had prepared, and a lot of the arguments he wanted to make.
Then the chair said that he allowed everyone to talk as much as he/she wanted because the chair didn't feel like 5 minutes were enough.
The session closed without a proper critique of the papers by the discussant, and with no questions from the audience whatsoever.
I wanted to make a question or two to one of the presenters.
Can such a chair be reported to the organizing institution?
Yes, you can complain. There is no reason not to if you are dissatisfied even if all of the prior expectations are met. But the organizing body may do nothing or it might just not ask that session chair in the future. There is probably nothing that can be done in the case you cite unless you are willing to contact the presenter.
But that is also something that is acceptable. Perhaps you will both get access to the slides skipped and get any questions answered.