Unlimited debits from Rain

Rain claims it data SIM is activated for month-to-month unlimited data. I have signed up for this service more than 11 months ago. In between months, I have decided to not pay nor use data (since their just block/deactivate the sim anyway, until you pay) for a month or so. It occurred to me (more than 3 times) that Rain says I owe some money, even after I have paid the monthly agreed fee (R479). I prepaid for September on the 29 August full amount. Yesterday they debited my account with another amount of R125 or something. Today, before I could write this review I have received an SMS telling me that "I have missed Rain payment. To stay connected I should please go to my-rain app to or visit www.rain.co.za/my-rain to settle my bill." What are these extra hundreds that they collect? Are they for reconnection?