Pathetic Service , Pathetic Company

I canceled in July and my cancelation "ended" in August I gave my months notice but they keep on billing me, thank heavens I did not sign a debit order with them or they would've just kept on deducting. My account has been canceled but I keep on getting billed. I obviously do not pay as my service has been canceled, Every time I complain, oh we will escalate your query and nothing ever happens, I do not even want to know how they ruined my excellent credit score. Will NEVER EVER recommend them to anybody, not even my worst enemy