Pathetic Service

I have been dealing with the cancellations department and has done an enquiry to cancel my tracking unit as it expired in November 2022. The email I received confirmed this "Please be advised the warranty of the contract for the BMW 318i falls as of November 2022 meaning to have this contract cancelled in November there will only be a 30-days notice one month premium which will need to be paid" I gave notice on the 01 November 2022 and this was my 30 day notice I provided which means that as of 30th November 2022 my service should be cancelled and no further debit order should be deducted. A debit order went off on the 23 November 2022 and my services was disconnected on the 22nd November 2022 which makes sense to me. I then had no active services since the 23rd November 2022 but to my surprise Netstar deducted money again on the 23rd December 2022 for a service I don't even have. I phoned the finance department and got told that i was billed for the notice period which is wrong as my notice period was November already. I would like my funds refunded for December 2022 or else I will take this further. I do have everything in writing. Its not a big amount but this is no on this is ****************.