Unauthorized debit order

I think this service provider is a **** and unless something is done through the relevant structures and regulatory bodies such as the consumer tribunal they will continue with their disservice. I cancelled my subscription with them in December due to poor network coverage and even received a call confirming my cancellation from them. Now they have double debited me and they are uncontactable. The bank cannot reverse the payment because they debit directly from the card. I will have to personally go their offices if they do exist to demand my money back