Making it impossible to cancel a subscription

So Dotcom Africa phone one of my staff members March 2020, who unknowingly signs a 12 month advertising contract for R8000. After a request that it should be cancelled, because I, the director did not sign nor authorise it, they responded: Its my problem. So I pay a cancellation fee ( which is 75% of the total fee). I receive an invoice which says: Cancellation fee. I pay the fee. Now one year later, I receive another invoice for a year subscription. I rep**** with the invoice and communication that it was cancelled in June 2020. Their response: I never wrote a formal cancellation letter attached to my POP?