go wherever you can speak with a real person… and thrown yourself at their feet… 
once when OH and I had a problem… my Mairie contact, spoke with her CPAM pal and the answer was… don’t worry, it’s a computer hiccup. Hmm I still worried, but it did get sorted and I felt better that a “real person” at CPAM was aware of our situation.
Well, to close this one off it was really quite simple. Appointment with CPAM at Loches for “change of circumstance” booked on-line via Ameli account. Took S1 with me (plus CV and CdeS). The guy scanned it, updated the file, assured me that the CV will continue to work during the change over and that was that, he did not need to keep the actual S1 form itself. Hopefully not “famous last words”!