Originally Posted by
GMOChicken
The upgrades are run by plusgrade.com & not directly by Vistara, maybe if you try calling Vistara they can upgrade you directly using the original card.
FWIW I'm surprised the original purchase worked with a US issued amex, that's never worked for me purchasing directly on the vistara website.
That is helpful I didn't make that connection Very unfortunate.
I've booked 4 flights since last year directly with AirVistara, always using a US Amex. I do get the Safekey Extra safety measures but payments all went through.
I only had one Indigo purchase but that worked the same way..