I wonder if what happened is that their system noticed that the dog had been licensed and no longer was, and so flagged it as a violation since the system had no concept that a dog might pass away or move elsewhere. I hope that in the future the default assumption is that residents in long-standing compliance have a good reason like this if their status changes. Maybe they should have a form you can return and nice "we noticed that you have not registered your dog, as you usually do; what's up?" letter to send the first time.

Also, a week is not a very long time. It's got to be shorter than the Mean City Hall Paperwork Turnaround Time.

Sorry for your loss.