You have until the last day of each month to have a paid membership and remain in the matrix.
If you miss a membership payment you lose your position in the matrix, as only active/paid members go into the matrix. So if you missed a month/payment and then reactivated your membership again later, you would get a new position in the matrix at the bottom following your enroller.
You still have your personally enrolled and will still get paid on everyone you enroll and receive matching bonuses on their matrix commissions according to the pay plan. So the only thing you would miss out on is your own matrix commissions.
Keep in mind, we send out 4 email reminders at the end of each month to anyone who has not paid their membership for that month to remind them to get their order in so they don't lose their position.