I would really appreciate any advice anyone can offer about how to fix this situation!

I booked a KLM award flight in J through Air France's website yesterday at a great rate, and received a confirmation email. When I looked up the flight on KLM's site, I was able to pick seats and everything. Later, I went to look up the flight in the KLM app on my phone, and got an alert saying it had been cancelled. I have no idea how I would have known this flight was cancelled, since I still have not received any sort of notification about that.

So I called Flying Blue and was told that it had been cancelled because no payment was received. There is no way to book an award ticket on the website without having enough miles and without entering your credit card information, so there must have been some sort of system error. I checked with my credit card company, and no attempted charge was made. In fact, Flying Blue support now claims there is no credit card information attached to the reservation, which is odd because it mentions my credit card type in the confirmation email I got. I know the credit card information is correct, because it gets auto-filled in my browser and it worked for another award flight I booked just 10 minutes prior to this one.

Unfortunately, it now costs nearly twice as many miles for the same flight in J, so re-booking it online is not an option unless there is some sort of delay before these seats are released, which has not yet elapsed.

After speaking with several agents over the phone (I kept getting disconnected 5-10 minutes after they put me on hold to look into the matter), I finally reached one who seemed to immediately grasp the situation and said she would fix the situation. Let's call her Agent A. She said she'd call back in an hour or so, because she needed to talk to a different department and wait to hear back from them. She ended up calling back several hours later, but by that time I was already asleep. She left a voicemail and followed up with an email saying that a new reservation had been made and I just needed to call in to make the payment for it.

The problem is, this reservation is for economy and premium economy! It turns out one of the agents I had spoken to earlier (but got disconnected from) had made this reservation, seeing that there were no more J seats available at the original fare. I suspect the department Agent A spoke with must have seen this new reservation and gotten confused by it. I have since called back several times, but no one seems to be able to help change this new reservation to J. They all keep telling me that they're not able to help because the original fare is no longer available.

Does anyone have any advice for how to handle this situation? Do I have any hope? It would be very disappointing if I end up with much worse seats just because there was some system billing error, that I'm in no way responsible for.