There are several possibilities:

1. It is not the merchant's own POS machine, but the third party put it there for use (there are various preferential policies).

2. The registered address of the merchant is different from the actual business address of the store (the registered name is shown on the bill).

3. The merchant's POS machine is a code skipping machine.

Extended data

Precautions for POS card swiping:

1, not too early: try not to swipe your card before 9 am, not too late: try not to swipe your card after 10 pm.

2. Try not to brush the 0 rate.

3. Don't swipe the same card more than 3 times a day.

4. Don't brush all the places.

5. Don't pay it all at once, but brush it all at once.

6. Credit cards are paid in small installments every three months.

7. It is best for a single consumption not to exceed 50% of the total card amount.

8. No one is allowed to check the balance on the POS machine before swiping the card.