Rain poor service delivery and unfair charge bills for services not received

We are using Rain as our internet service provider. Wi-Fi. We signed up for the month to month option. So if you don't pay you don't recice ant service. Now 3 months ago we decided we are taking abrak from our Wi-Fi service. Now when we wanted to reconnect Rain said we owe them R1320 FOR THE 3 MONTHES WE DIDN'T USE THE SERVICE.... As you know you can't phone anyone for support just the message on the app... I do not understand how can you owe money for a service you didn't use that is on a month to month basis.... Can someone please advice...