Hello... Is there any intelligent parson working at Mixtelematics?

I have had an accout with Mixtelematics for many years. In November 2019 i realised that I was no longer receiving value for money. I called the company to discuss cancellation procedures and was informed that I could cacel over the phone. I was informed that 30 days notice is required but that i could cancel straight away. I gave my notice to cancel there and then on 12 November 2019 and received an email confirming that tha service would be terminated on 13 Decdmber 2019. I rep**** to this email requesting clarity on the billing asking if the amount would be pro rated. I did not receive a reply. On 2 Dec the entire subscription amount was debited from my account. I received another email confirming that my account would be terminated on 13 December. I called the company to discuss the bill. I was sent from pillar to post with the same response that the company does not pro rate the bill. In exasperation I asked to spesk to a manager who was extremely rude and condescending and maintained that 30 days notice was required. I informed her of the emails from the company confirming that the service would be terminated on 13 December and that it is unfair to bill me for the days I was not receiving the service. She insisted that the notice from 12 November to 13 December constituted 20 days notoce! This is ludicrous. Would this mean that I only received the service on business days? She indicated that she would check with the debtors department. On 13 December a consultant from the debtors department called and again insisted that the company does not prorate the bill. I asked to speak to their legal department but have not heard from them. Mix telematics cancelled my service on 13 December but billed me for the full month. This is **************** and unjustified enrichment. How is this justified? Disappointed long term customer.