Rain is nothing but disappointing

I have ordered and started using Rain 5G as of 5 September 2023. The service has been utterly poor with little to no connection. I have switched off my router which I no longer use since 13 September and have moved onto a different Service Provider which has thus far given me no problems. It is 3 October 2023 and now Rain wants to charge/debit me over R1400 for services. I have no problem paying for a month (R560) for 5 September 2023 until 5 October 2023 but I refuse to pay all this money for something that gives me no service. I want to cancel it immediately but now I am told I cannot cancel until I pay this full amount. I am a single mom and cannot afford this. I chose Rain for its price and what it offers on adverti*****ts, but what a ****! I will never recommend you to anyone! Please let me cancel, I will pay you for a month and leave me alone. Thank you