I had an even more time consuming experience like this. I worked with Apple Support over the phone for a few months. They had me install a profile on the iPhone to collect more diagnostic logs, had me perform various steps to reproduce the issue, followed up for more information, etc. After a few months, the person assigned to the case went on vacation or something and another person was assigned. Coincidentally, it was getting closer to a new iOS release date. My whole case went completely dead and there was no way to revive it.