The process for returning a transaction that has been paid by card is the same as a regular return. Enter the amount to be refunded in the Credit Card tender box, then proceed through the next steps as normal.
The screen on the Paymentsense card terminal will show the value to be returned, but this appears as a positive amount when you may expect this to display as a negative amount (i.e., you're returning £10.00 to the customer's card, therefore you may expect this to appear as -£10.00 on the card terminal, since the Total Tendered amount appears as such in the POS screen).
This is normal, the terminal just doesn't display the value as a negative amount. When the customer has presented their card to the terminal and the subsequent receipt is printed from the card terminal, you should see that REFUND is shown on the receipt.
