IQ Center keeps the list of customers whose call was missed and who were never called back. It is not a counter: each line is a number, with how many times they tried, which queue they reached and how long they have been waiting. The line disappears on its own as soon as one of your extensions calls them back.

Knowing you missed 40 calls last week changes nothing: it is in the past, and nobody knows where to start. Knowing that eleven specific people are still waiting for a call back is a task someone can complete this afternoon. That is the whole difference between a statistic and an action.
It counts people, not calls: a customer who tried to reach you three times appears once, with their three attempts.
As soon as one of your extensions dials that number, the line leaves the list — nothing to tick off or update. Same if the customer calls again and gets an answer: they were served, so they no longer belong there. That is what keeps the list trustworthy, and what keeps your team using it after the first week.
The criterion is deliberately strict, so the list does not fill up with noise: the call must have entered a queue and waited at least ten seconds without being served. Immediate hang-ups and direct calls to an extension never appear. A call that abandoned in a queue but was eventually picked up by an extension is excluded too.
IQ Center compares missed calls against outbound calls from all your extensions. As soon as a missed number is dialled by one of them, it counts as handled and leaves the list. No manual data entry is involved.
No. The list counts people: they appear once, with their number of attempts. You only have one call to make.
No. Every call is tracked end to end by its unique identifier and attached to the last queue that handled it. It cannot appear twice in the list.
Yes. It filters by queue, by agent or by location, and a manager can be restricted to their own scope so they only see the customers that concern them.
Open the live demonstration — real functionality, fictional data, no signup. Or talk to an expert who will show you what it would look like on your 3CX.