I realize that you guys might be doing everything correctly and are still getting screwed by a glitch that no one can nail down. Please consider these just suggestions and not any type of condescension.
I start by using the “Create New Event” option. I used to do the Ongoing Event when I first started but I found it very easy to screw up and overwrite previous sessions. Keeping each event separate is very helpful to my busy mind.
When I report a session, I start by entering a “1” in the Session # box. I know that’s so obvious, but sometimes it helps to point it out. If you are reporting multiple sessions in the same event, you need to enter the sessions sequentially. If this doesn’t make immediate sense to you, it is probably how your reports are getting eaten.
I use the Tab key to advance from field to field. When using a database, this is a good habit to fall into. If you need to go back to something, hold the Shift key down and then hit tab and you can go back instead of forward.
The GM # is your Pathfinder Society membership # without any -1, -2, etc. If you get an error message after you Tab out of the field, it’s OK. It’s a persistent error and all it means to me is things are going as expected. I’m so used to it, if I didn’t get it I would back out and start over. When you enter your name after your GM # (and acknowledging the error message), make sure that you spell your name just as it appears on the Paizo account you registered with the Pathfinder Society. I’m not sure it that matters, but it’s a good practice.
When I have finished entering each session, I will hit Update and let the page refresh. If I have another session to report I will hit “Save Changes And Report Another Session” (Sorry! I know this is painfully obvious!).
It is really important to enter the information 100% accurately the first time around. I have found that the session info in a player’s account is very stubborn and will not accept editing afterward, like a CD-R. An organizer can change the info on the event reporting side, but it will not be altered the player’s account after the first time the organizer exits from the session page. Get it right the first time, or be prepared to live with unhappy players.
If I am finished reporting a session, only then will I hit “Done For Now”. That will take me back to the event reporting page, where I click on Sessions next to [Clone/Edit/Report]. If the sessions look good and correlate to what I have on my session tracking sheets, I will go back and click on Report again, bring up session 1 again and click on “Mark This Event as Completely Reported”.
I have reported 88 events on the system (20 of those are multi-session conventions & gamedays) and I have made my share of user errors. Even after GMing over 150 sessions of PFS scenarios I’m not throwing stones because my house is definitely made out of hardness 1, 1 hit point material. Again, I apologize if this comes off as condescending. Consider this a shot in the dark to help other organizers who may be having the same problems, or are afraid to try reporting because of these stories.
I would recommend that you keep trying to report your sessions if they don't take the first time. What's the worst that can happen, right? I doubt they will suddenly appear on their own at a later date.