Overcharged for no reason.

Rain over charged me way more on my rain account than I expected. Last time I used that sim was mid Jan. I couldn't make payment in December and Jan. And I got charged R940 for that which made sense. However even that I couldn't pay so my services got disconnected. Since then my sim card hasn't been working at all. Now imagine my surprise when I get debited R1410 plus R470 on the same day. Now I'm wondering how I owe that much when I have been suspended since and I haven't been using the sim since. And we're told it's not on contract but a pay as you use kind of service. How does that even make sense. I'm so disappointed with rain.