I think I guessed wrong about my experience with flight plans in MyRadar. Today I tried filing a flight plan through 1-800-wx-brief, which checks thoroughly to be sure a flight plan is complete and correct before accepting it. My plan was accepted, so I'm pretty sure it was good. But MyRadar couldn't find it. So I tried a few other online sources to see if it was really there. One of them came back with "The Tail Number - N123XM - is blocked from public viewing."
And that's when I remembered that after ADS-B was mandated the FAA developed a form that would prevent the general public from viewing ADS-B data if the aircraft owner requested. I made the request, and since then FlightAware and the other flight tracking apps can't find and track my N-number. So now I think that explains my invisible flight plans. It was my own fault.
And that probably means iFly isn't implicated at all.
That doesn't mean iFly doesn't have a problem, of course. It's just no evidence at all, neither positive, nor negative.
(What surprised me now is that it's the N-number that's blocked. I'd been thinking it was simply the ADS-B data. And now I'm re-thinking my request that the FAA not publish my location. Originally I was concerned because I do a lot of water ops--meaning my plane is often close to people who know how to find its N-number online. I try always to keep the legal distance; but "500 feet" is is hard to pin down, and I didn't want to have to defend my legal flying. But now I may change my mind.)