Bad service, wont allow cancel even out of contract

The internet service with talk talk has always been average and I out lasted my contract though I was ok with allowing the internet service to continue, which was more down to my laziness. But enough was enough of slow internet and that's their Fibre 65 which is supposed to be great, sadly not. I now have tried on three attempts to cancel my use of their service and its like they don't give you an easy option to cancel. They try to push it on my new provider to cancel with Talk Talk which seemed weird to do so but Three who I have moved to said it was 100% on TalkTalk to cancel it. After my third attempt of telling them to cancel and well within my billing period (12 days) before the next months usage would be used they have told me I am to act like I'm using the next months internet and i then pay for it and then also send them the equipment back in that time. Why should i pay for another month that I won't even use as I made it clear I am already using Three's service.
I was wondering what would happen if i just cancel the direct debit after I pay this this months internet which I also asked the advisor? I was told not to do that, and see out the extra month I won't even be using.
I then also asked could I get the transcript of this phone call or more info on all that we have spoken about as well as the instructions in this cancellation process. I did not get this I instead get an email 'We'd love for you to stay" - We'd love you to stay, and because we know that value matters to you, we'd like to help you find a new plan that works for you. It could save you the hassle of leaving.
I called them three times and its like talking to a wall they are so difficult!