Amazon and business invoices…again

We just got an email that >5% of our Amazon-Business customes got no automatically uploaded invoice.
That >5% is 1 of 1 business order in a year = 100%.
We actually have automatic upload of invoices seet up.
However the Amazon API only allows to upload an invoice.
Not to check if that upload worked or if an order already has an invoice.
The log also shows that indeed an attempt at an automatic upload was made.

There is also no way with Amazon to only supply end-users and not accept orders from businesses.

We contacted the company that provides the Amazon-integration plugin we use but since this isn’t the first time, there will likely not come anything from this.