American Express Reason Code C31

What the cardmember received doesn't match what was advertised.

A quality, accuracy, or condition mismatch between the listing and what actually arrived.

The product listing as it appeared at purchase and any support correspondence are the core evidence.

Dated snapshot of the listing at time of sale, product specs, and support correspondence about the complaint.

Not archiving dated product listings, so you can't prove what the customer actually saw.