VITALITY DOES NOT CANCEL DEBIT ORDER AFTER WRITTEN INSTRUCTION AND TELEPHONIC CONFIRMATION

I have requested the cancellation of my Vitality membership, in writing (26/09/2019 for cancellation on 1 November 2019) and have received reference numbers, but nothing has happened since my first request. Even after confirming by telephone on 7 October 2019, that the cancellation was to stand, nothing has happened. I have just just been charged again, for a service cancelled as from 1 November 2019. PLEASE FIX. I HAVE FOLLOWED UP WITH FURTHER E-MAILS ON 4/11/2019, WITH NO RESPONSE AS TO CANCELLATION OTHER THAN YET ANOTHER REFERENCE NUMBER ***. WHY THE DEBIT. WHY DID YOU BREAK YOU CONTRACTUAL TERMS AND *******LY DEBIT ME?????? WHEN ARE YOU GOING TO REFUND ME??????