Double billing for service I did not use

I have been using Rain wifi for few months now on the R699 month to month deal. The signal is always bad and I'm not even far from the tower, I have been paying every month but now that I skipped last month because I was not using the wifi I am told they going to double bill me this month if I want to access again because somehow they say I am in arreas for data I used from 1 September 2021 to 30 September 2021 which does not make sense at all because my service was deactivated already on 8 September and I did not touch it and even plugged the router out. How do I get billed for a service I did not use when it's month to month and you pay as you use. I called and was told I would be assisted but still no feedback and got a ref number: **********. I am definitely not going to pay double for a service I did not use, I really don't trust Rain and I always struggle to get through to them, it either rings and then hang up or you wait forever on the line. I want to cancel the service now because I am being billed for imaginary use of wifi and now they don't even allow me to cancel on the app because it shows I'm in arreas on my account. If there is anyone at Rain, please cancel my service as your advertising state that you can cancel any time because I won't be using it anymore and definitely won't pay. Rain really seems like a **** or someone is trying to make money of the customers. I've seen so many complaints about other people also having double billing issues. Today I am being told they charge you the same R699 whether you use the service or not, how does that work when it is not a contract. They say this is the same way Netflix and Dstv work which is false, since when do you get charged for something you did not use. I have both Netflix and Dstv and never had to pay double for something I did not use. I am not paying and also their terms only state you get billed if the sim was used so I don't know how they can charge for a month for a sim they say is active when it was deactivated by them already on 8 September. My last payment was made in August and after August haven't been using it.