Why doesn't 4g Lacarra charge money?

Lacarra does not charge customers for spending by credit card, but it does charge merchants' fees, which have been deducted when merchants' funds are credited.

The use process of Lacarra pos machine is as follows: 1. First, you need to turn on your computer, and then press any key to log in. 2. Enter the operator number and password according to the system prompt. 3. Press 1 to select consumption. 4. After entering the customer's consumption amount, press Enter. 5. The magnetic stripe card is swiped in the right sensing area, and the chip card is placed in the upper sensing area of the machine. After entering the card password, click OK to finish swiping the card.