Supersonic failed to cancel my Account now being handed over four years later

In June 2020 I canceled my Nepic/ Supersonic account via email to their Accounts dept Each month until September I was debited and I sent an email each month saying that I had canceled the account Then 4 years later I have now got VVM collections phoning me claiming I owe Supersonic But no body at VvM or supersonic can supply me with a detailed statement as to how they get to this amount I have now been told I need to prove to VVM collections that Supersonic cancelled my account even after I supp**** them all the email correspondence Supersonic also cannot find me on their system to even assist me