As of today OPM has still not responded any further to Congressman McDermott's office; my contact has been leaving messages. I decided that since it's been a week the chances of my case being wrapped up by the end of August were looking pretty slim. So I've contacted the insurance company and started the conversion policy process. I'm glad I didn't wait any longer than today, as that paperwork has to be postmarked August 20 for my coverage to begin September 1st and remain continuous.
I'm keeping track of all this so that OPM can reimburse me. But it still makes me angry. I can certainly see why they advise starting your standard retirement process 5 years before your actual retirement date.