GetMore247 Cancellation Horror

So I have cancelled this service, and the again it was invoiced against my December bill. So I tried having it resolved with Gavin, but with his attitude im getting no where. I even gave him the statement clearly stating for 01-Des-2018 till 31-Des-2018, his reply was no matter what the statement say, i still must pay for November, then i showed him on the same statement i already paid for November. He just keep saying I mustn't look on the dates of the statement as they are not the correct dates.