Breach of Contract Terms and Conditions - ******* debit order after Contract Cancellation

I cancelled my Supersonic contract in October 2020, under the guidance of their Terms and Conditions I accepted that it must be a calendar month's notice. I received a sms informing me of Supersonic submitting a debit order request earlier in December, to which I responded and informed them of the cancellation, as well as submitting acknowledged proof sent from Supersonic to my email address of Supersonic accepting my cancellation.

I have just been debited again. This is outright theft! I demand I receive a response and a refund! Do not use Supersonic! They are deceptive and their lack of communication and service is unacceptable.