I heard the answer to my question: right now, you have 30,000 unresolved complaints.
You also mentioned that you have increased your capacity to deal with complaints. If I'm not mistaken, you said that you used to process between 5,000 and 6,000 complaints annually and that you are now processing 15,000. So, it will take about two years to process the entire backlog of 30,000 complaints. I imagine that you have plans to continue improving your processing speed so that you can handle more.
You also mentioned that a large number of complaints were resolved through facilitation and mediation, which was the primary method used.
I think you also group complaints, to deal with a number of them.
Once the complaints are considered closed, do you call the complainants back to find out if they were satisfied with the outcome? Do you have any statistics on complainant satisfaction?