Well, since neither of us can physically verify the data that was transmitted between the two parties, I supposed we will never know what actually occurred or who was at fault but if we hypothetically assume that Hertz did indeed send the wrong information (despite being accurately reflected on the rental record) as you allude, then PlatePass must still assume liability for failing to verifying that the information they received is correct.

Any merchant which has the privilege of accepting credit card payments is liable for technical errors regardless if they received inaccurate information from a third party. It's their responsibility to verify that they are billing the correct customer if they wish to sustain an active merchant account.

I personally find the whole PlatePass business to be rather questionable and most experienced renters know to steer clear of them, yet we can't escape them no matter how hard we try. Even when we don't use them, we can still get charged. Then we must invest our own time and resources to resolve the discrepancy, assuming we ever notice it at all.