Is the last 4 digits of your credit card different to what's shown on your receipt?
If you paid for a trip with Apple Pay or Google Pay your trip receipt will show the last 4 digits of your virtual account number as opposed to the last 4 digits of your credit card.
Your virtual account number can be found in the Apple Pay or Google Pay apps.
Open the wallet app on your iPhone, tap on the card then at the bottom right of the screen select the ℹ. Tap on information and you will now be able to see the last four digits of your Device Account Number
Open the Google Pay app on your phone. Select your credit card and scroll down until you see your Virtual Account Number.