It could be just that they needed to verify it was you who applied (Identity verification).
If you have SSN/ITIN, you can also check app status at
Status Check Authentication
Sometimes you can confirm that you are the one who apply there by entering some more details.
If you already have a card with them, I do not think they will ask for address verification again. If they do, you can use your existing card details.
I heard sometimes they want to ask about your business like what you do or why you want a business card. Can just tell them you need to keep work expenses separated.
Soemtimes you can get approved even without calling.
Have you called?