If your plan is one of the legacy plus plans(look at your account under plans) you might have to select one of the new plus plans to be able to select monthly. If you are base plan and within 7 days of your due date open the app, under the accounts tab click the arrow by service and plans, scroll down to plans and tap on the switch plans box, there should be a tab that shows pay monthly/pay annually, click on pay monthly then tap on select this plan at the bottom, it should switch you to monthly. If you are on legacy 1 or legacy 2 plus plan I believe you need to select one of the new plus plans, either the regular plus or the plus pro, then you should be able to switch to monthly. If the monthly option is still not available after selecting one of the new plus plans then you need to contact customer service and to see about what the issue is.
