The secondary card is charged with phone charges and can be used together with the main card. The secondary card is a mobile phone card that can be used independently, and the user must register the real name authentication information with his\/her ID card before normal use. The sub-card and the main card are independent of each other and do not interfere with each other, but the sub-card's business is bound within the scope of the main card's package business, and the main card uses a package fee together, so that the sub-card can use this part of the bill together with the main card after the call fee is charged.
There is no problem with the charge of the sub-card, because the sub-card is bound to the main card, the charge of the sub-card is shared with the main card, so don't worry about the charge of the sub-card and your call can be used.