Extremely weak connection and customer harassment on cancellation

Decided to finally disconnect my router on the 27th of January 2022 unplugged it and sent a cancellation request on that same day due to extremely poor internet connection with rain and I had really had it, and because the data for January was already used, I was liable to pay the month of January fully, which I did and yet I was still billed for February regardless of the fact that the router was last in use on the 27th of Jan and cancellation request was sent as well, to top it all off I had an angry agent call me telling me that they will not cancel my plan up until I pay the outstanding amount which includes the February bill but I refused because they say its a pay as you use, I'm on the 5G uncapped plan costing me R999.00 a month and it was not in use in October and November 2021 and because of that my bill was set to zero and now all of a sudden It cannot just because I am cancelling due to poor connection??

So Rain is going to provide me with a weak connection and when I want to cancel the month to month plan then they punish me for cancelling?? and still make angry shouting agents to call me trying to force me to pay?

I am not going to be bul****, I have emails, images, names, statements and reference numbers to back me.