Unfair billing

I cancelled my fiber services with Vodacom on the 11 March 2024 because Vumatel's minimum speed was changed from 8mb/s which is where I was before, to 50mb/s which meant it was more expensive for me than before and I couldn't afford it anymore. The services were suspended because it was a month to month service, and i switched off the router because it was not in service anymore. however I was still billed, I called Vodacom to get clarity, but they kept saying I should send them proof of cancellation which I did several times because I was talking to different people every time but the proof was sent to the same email. then I was told I shouldn't cancel via email, which was strange because on the document, email is mentioned hence they have it, I even sent them that as proof. Then Vodacom decided to send me to their lawyers to settle the payment. What kind of treatment is this by service providers? This is crucifixion and unfair. I'm not happy with this kind of treatment.