It's difficult for us to work through all of the submitted issues because most of them are from students who don't understand the problem or have made a mistake in their work, not real issues with the content. We always keep an eye on the number of issues per exercise, and we're lucky to have volunteers who read through the issues and surface the real issues.
You don't have an insurmountable problem. It might take a week or two for one or two individuals to catch you up on filtering out junk submissions and organizing the rest. But a volunteer, unless they are familiar with your priorities, resources, and the nature of valid issues in your systems, probably can't do it.
But that beats dealing with complaints like this pedagogical complaint on an ad hoc basis. If they could track their issue and see progress being made, they wouldn't be yanking your chain. In fact, in my cursory examination, I didn't see content issues being tracked. You must have a few of those.
Problems like this one should get tracked and resolved through this system, but the system could be stalled.