Support for customers with a prepaid balance reduced by calls made


Is there a way to bill a prepaid VoIP customer? For example:

Customer opens account and deposits $100 + taxes (Avalara). Their opening balance is $100.

They make calls with each rated CDR deducting from the $100.

Once the available balance goes under $10, they want to refill with another $100.

Is there a suggested way to make this work with Sonar?


This already works, once you invoice the calls.


Sorry, I don’t see any way to actually make this use case work. There isn’t any prepaid functionality visible in the portal so I’m trying to figure out a workaround.

I tried posting CDRs and then generating an invoice, but it’s not finding any “debits”. Should I be posting one-time transactions myself to the account via an API every day?

Usage for 2019-01-28 $1.23
Usage for 2010-01-29 $5.23

I don’t see how that would trigger anything automatically based on the remaining balance in their account though.

I could also maintain the usage/balance on my end as I do now and just use Sonar to generate a $100 invoice and send to the customer, but then Quickbooks could do that too (minus the Avalara integration).


Hi Ketan,

It’s probably worth reaching out to support to work through your use case, I think this is more than is simple to explain in a forum post. If you prepay $100 and generate subsequent invoices, the invoice will be automatically paid by the prepaid amount, but I think you have more going on than that.