I lost a big project half way through, lost money because I bought new equipment to do it. I should have sued my customer over it, I had the PO, but in the end I would have been slitting my own throat by burning the bridge for future work. They were just the middle men anyway, it would have meant them going back to the end user, a pipeline supplier, and they probably would have slit their own throat as well.
A happy medium is what is best, but no one can even say what that is without a fight.
I’d make sure my customer was aware of my decision, and I’d try to make sure they don’t forget it when the storm clouds lift.