You pay for your service upfront.
Today is June 18, 2016. You pay today for 30 days of service. Your next pay will be 30 days later.
13 days of service starting on June 18.
17 days of service on July 1.
Next payment is July 18, 2016. (Which will be day 1 again)
Get it...got it...good! :)
If you dont pay your service will be turned off.