This was an incredibly painful experience. I think you are literally the most difficult business I have ever had to deal with.
It took my daughter 3 or 4 tries to send her driver's license. The failed times, the software accepted the upload, only for us to find out later that "something went wrong". No explanation, no idea how to fix it, not even any notification at the time it failed. All we got was a message a few days later that we still needed to supply documentation, and when we logged on to the website, we THEN saw that she still needed to supply ID.
She eventually figured out how to send you something that you'd accept for ID after calling on the phone (more than once, I believe). You at least answered the phone, which is good.
Then, just after she managed to send an ID that you'd accept, you cancelled the application because it was taking too long, and we had to start over. ("Start over" is a bit too strong, because we were able to import most of the data from the previous application, which was helpful.)
We finally finished the application. I got two emails within five minutes of each other. One said "We're ready to disburse!" The other said "You need to fix something on the application." Well, which is it? Are you ready to disburse, or not? The answer was no, you were not - not until I fixed whatever it was.
So in summary, it's mainly about feedback. Feedback should be fast. If something failed, tell us then, and tell us why it failed, and how to fix it. Don't tell us some days later when you send a periodic update.
And, feedback should be consistent. Don't tell me yes and no in two emails five minutes apart.