Cancelation of TV licence

I sent them an email on 15 November 2019, to cancel my license. They never responded, but handed me over to Debt collectors. I sent the same email to their Debt Collectors, twice. And I spoke to the agency telephonically and informed them. Still no response. On 18 January 2021, I get an email with my latest account, with monthly charges. I have no idea what to do to get thus resolved since none of their administrators are reading my email