With Nextiva Connect we send a pro-forma invoice to the email address on file 5 days before the monthly recurring fee is billed to your card on file. Nextiva service is billed in the beginning of the month and is pre-paid toward the new month you are entering. The monthly recurring subscription fee is not billed in arrears.
The only arrears billing with Nextiva Connect would be overage charges for going over your monthly minutes or any toll free calls to your Nextiva Connect account.
Example: I begin service on January 1st and I am billed for the monthly subscription fees upon sign up. If I have a 500 minute plan and I use 750 minutes during January, the additional 250 minutes I went over are billed along with my next recurring subscription fee on the February 1st.