ApplePay doesn't provide the card reader with a single use number. It provides it with what Apple call a DPAN (Device PAN). This is setup when you add your card to the device and the card scheme back ends can map this to the physical card. There are other transaction specific security elements, but the card reader sees the same PAN each time. If it didn't systems like contactless travel on London Underground wouldn't work. TfL wouldn't be able to tie your entry to and exit from the system together.
Biting the hand that feeds IT
