In MoceanAPI Verify, we put our customer first and allow our customers to choose a desired charging model, one of them are "Charge Per Attempt"
The way it work is you only pay every time you send a code to your users at a standard rate, however we have Number Lookup feature integrated with our verify feature to ensure your value.
We will lookup to the number before we send the code, if the phone is not available in the first place, we won't be sending the code into the void, and we will only charge you by number lookup rate instead of the standard rate.
For further assistance, do raise a support ticket with our Support Team at support@moceanapi.com.