rain does want to cancel month to month subscription

This mobile network operator is frustrating, I have a month to month (monthly subscription) with them and I can cancel anytime, when want to cancel you can only do it via raingo.co.za where you chat to a robot, however they don't cancel in time and then they let it fall on to the next month, when complaining the the robot chat "Leila" keeps on saying it is escalating your issue and it is a high priority. When calling their call center there is no option for cancelling or speaking to a call center urgent. I have not used any of their data this month because I cancelled last month and I do not want to incur any cost this month.