Which statement about paying a traffic penalty after receiving a traffic penalty notice is correct?

1. ①It must be paid within 30 days of receiving the notice.
2. ②If not paid in the first period, the traffic penalty plus 20% must be paid within 20 days from the day after that period ends.
3. ③If it could not be paid in time because of a natural disaster, it may be paid within 30 days after the cause ends.
4. ④Even if the traffic penalty was paid on time, the person can be punished again for the same violation.