It seems my Mondo card sometimes gets rejected at various toll booths on the French autoroutes. I can’t see a pattern other than it’s always the same booths and i think when the amounts are higher (in the €30 range). I’m not sure on what grounds they’re rejecting it, my phone is with me and roaming enabled and i have more than enough to cover the amount.
I can give more details about the exact locations if required.
Cheers!
Lee.