I wouldn't pay a penny over that. Panther says you should have called, but that's because they want to put the blame on you. If you got the AWB# from Panther, it's all on them, regardless of what was on the QC insofar as pieces and weight.
When I was at Panther the pieces and weight on the QC load offer was wrong so often that I started to regard it as merely a ballpark estimate. I tracked it once over a 6 month period and the QC information was correct 39% of the time, incorrect 59% of the time, with 2% being NA (0-pieces, 0-weight). In the OPs' case I'd have done the same thing, which is double-check with the shipper (you know, the one who knows infinitely more about their freight than I do), and once they confirmed what I was to haul, I'd simply communicate that via the QC Macro 3 as we were supposed to do, maybe wait 5 minutes if I was still a little unsure to give the dispatcher who is monitoring the load time to read the QC message (since, you know, that's their JOB), and then leave the shipper.
If there was a problem the dispatcher should have discovered it within minutes and had it sorted out quickly. In this case, the next day? Sorry. Once confirmed with the shipper and then communicated to Dispatch, it's out of my hands. Calling them and telling them the same exact information they are looking at on the QC screen is a waste of time. I'm not paying for a shipper's mistake or some breakdown in communication between the shipper, customer and carrier, and certainly not for a dispatcher failing to do their job.
On the other hand, if you failed to get the AWB# from Panther, you're screwed.