Starting September 9, 2019, we are rolling out a change to prevent the same 
Payments accounts in the Google Ads API (
billing accounts in the AdWords API) from being used across 
manager account hierarchies. Only valid Payments accounts belonging to the Google Ads manager account hierarchy can be used to create and update 
billing setups in the Google Ads API.
How does this affect you?
For your authenticated Google Ads client account
Therefore, you may get fewer results from those API calls than before.
What do you need to do?
Google Ads API
When creating/updating a new 
billing setup, you will need to select a 
valid Payments account returned by 
PaymentsAccountService.ListPaymentsAccounts(). If you use an 
invalid Payments account during the above processes, the 
INVALID_PAYMENTS_ACCOUNT error will be thrown.
AdWords API
When creating a new 
budget order, you will need to specify a 
valid billingAccountId (the ID of a valid billing account returned by 
BudgetOrderService.getBillingAccounts()). If you use an 
invalid billingAccountId during the above process, the 
BudgetOrderError.INVALID_BILLING_ACCOUNT error will be thrown.
As always, if you have any questions, feel free to post your questions on 
the Google Ads API forum.
 - Thanet Knack Praneenararat, Google Ads API Team
 - Thanet Knack Praneenararat, Google Ads API Team