Impossible to cancel a contract after the agreed end date

Impossible to cancel a contract after the agreed duration. I called the customer care 5 months ago to cancel the contract, over the phone they confirmed cancelation. 5 months later they still debit for the same canceled contract. This time no one assists over the phone, emails are not being rep****. Why do people have to run behind service provider after the agreed dates have passed, devices are paid for at that point why do they keep taking payments?

Extremely unfair to the client 🤬