Do you bill per order?
No. We charge per address validation attempt as every validation incurs an expense with our 3rd party validation partner. We can provide a discount if your store is processing over 50,000 verifications per month (~25,000 orders per month).
Can we get an email whenever an order is placed with a failed address validation?
Yes. You can implement a Shopify Flow workflow that handles this exact use case. We outline this on "Shopify Flow setup".