Reimbur*****t needed for inactive account

I have been paying a monthly fee for internet service for more than 15 years but never had the service. When I tried to cancel it years ago they said it’s on my dads name and he needed to cancel it which he couldn’t do as he didn’t even have the account details. My dad has now passed on so I want the account closed and the full amount to be reimbursed. Surely you should have systems that show ‘Inactive accounts’ and stop collecting money or at least stop the debit orders...when people want to stop accounts, your processes must be simplified - let me explain the magnitude of this. I have paid approx R15k for services that I never received for 15 years and your systems didn’t even pick this up. What sort of digitally advanced company are you? Please contact me as your website does not have an email contact or a BOT