The billing data related to the customer related to this payment.
All the fields in this object are mandatory, you can send any of this information if it isn't available, please send it to be "NA", except, first_name, last_name, email, and phone_number cannot be sent as "NA" Like below.

Correct Billing Data
"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"