Bad service from Rain

I canceled my subscription in December 2023 after almost all year without a network on my Rain Modem. I thought since it's a month-to-month contract I didn't think they had been billing me for all the months even if they did not receive payment. Long story short I was forced to pay R4000 odd to cancel the subscription finally. On 11 June 2024, I received an SMS that I am owing Rain R375,42 from Nudebt. I called Nudebt on *** to enquire and was told I needed to pay that additional cancellation fee, which I was not told about. I logged into the rain portal and indeed that amount was outstanding. I went ahead to pay and then called Rain on *** and no one answered my call after being on hold for 5 minutes. I called Nudebt back to inform them that I have paid and they confirmed the payment but could not issue me a paid-up letter. Rain customer service doesn't answer their phone and can't find the cancellation function on the portal.