Go my account, login, overview. There should be a button in the middle of the screen saying "change plan" under Account status. Click this button, click the drop down for your new plan, and either change on renewal date or change immediately. From wh...
Public mobile plans are for 30 days. You add funds to your account, and your plan renews for another 30 days. You can also autopay, you get $2 off per month with autopay and don't have to think about topping up your account every 30 days.
