at public mobile Prepaid Service No fees extra charges,
and they service 30 day not monthly,
you have to Contact Customer Support Agent by CS_Agent , Explain your issue to
they can solve your issue, they are nice Service Team they will help you 100%.
Here’s How To Contact Customer Support Agent by CS_Agent,
@moolahoops : Yes indeed...30 days...not monthly. No need to contact the CSA's. For your curiosity, it will take about 5 years for the date to inch up and come back around to your activation date.
Edit: For your budgeting purposes, you could make a manual payment on a set day. The system will take that money at the next renewal. This gets a little tricky when that renewal inches up to around that chosen payment date.