Billing data:

Billing data are the customer info that he provides when ordering a product or a service,

"first_name" ,"last_name" ,"email" ,"phone_number"   are the mandatory data that's required by the issuing bank and must be provided.

"apartment", "floor", "street", "building", "shipping_method", "postal_code", "city", "country", "state"  Must be hardcoded to be "NA" when you send it to Accept's server, you might keep the user's actual data but make sure you're sending the hardcoded ones.

 "billing_data": {
    "apartment": "NA", 
    "email": customer mail", 
    "floor": "NA", 
    "first_name": "customer firstname", 
    "street": "NA", 
    "building": "NA", 
    "phone_number": "customer phone number", 
    "shipping_method": "PKG", 
    "postal_code": "NA", 
    "city": "NA", 
    "country": "NA", 
    "last_name": "customer lastname", 
    "state": "NA"