You can view your billing logs in your Workspace in 'Billing log'.
Click on the name of your Workspace in the top right corner and select 'Financial' from drop-down menu → ‘Billing log’ tab. There you will find an overview of the SMS messages you’ve sent and the amount charged.
You can download your coverage report, see the overview of your expenses by filtering the specific period of your interest and export the data to an excel file if you wish.