Redmine - how to understand whose last activity was in a task?

Question

Helpdesk

Good day everyone!

I continue to deal with Redmine.
I set up a lot, but a couple of moments I don’t understand how to do it.
I rummaged through the settings, Google didn’t help either ...

The work begins with opening a table with all the tasks, for myself at the moment I found the table at host/issues

1 to be the most convenient. Many tasks are clarified before getting into work, the customer is asked additional questions, for this the task status is set. Specified.
The customer sees the table, sees the status Clarified, enters the task, answers the questions.
And here is the first question.
How can I understand what he answered after looking at the table after the customer's answer?
I understand that there is a common history of all tasks, there are email notifications, and you can also ask the customer to change the status of the task after the answer ...., but all this is either inconvenient or unreliable.
I would like to look at the table and understand that for these tasks the ball is on my side.

In fact, this is either a status change by event or the "Last responder" column, where I would see that if the last responder is not me, then the ball is on my side.
I did not find any ways to implement either one or the other ...
Perhaps this is done through plugins, but the devil will break his leg in them ...

2. Often there are situations when the task seems to be completed and even accepted by the customer, but after a week or a month, it turns out that this is not the case. Accordingly, the customer unsubscribes to the task, and after that I somehow have to understand that something is wrong with the task and take it back to work.
Again, posts, history, manually changing the status is not the best option.

How to automatically change the task status from "completed", "closed" to "returned" after the customer unsubscribes there (although in fact it is not so important by whom)?

Once I worked in OTRS, everything, if I'm not mistaken, was tied to events and worked without problems, what to do here is not yet clear.

Where to dig?
Plugins?

Through the rest api on the crown, pull tasks, for example, changed in the last 3 days, view details and change statuses?
But this is still a pitchfork on the water, because. I don’t know the possibilities of api, I saw it briefly.

Thanks in advance!