Cancellation of Contract

On 15 January 2018 I spoke to somebody at customer care as I want to cancel my contract. A from was send through to me which I have completed and send back to the cancellations department. They have deducted the money again from my bank account in March 2018. I have made 8 calls of which the duration was 1 - 2 hours each in February 2018 to find out if my cancellation was processed, but nobody can give me a answer. I wanted to find out what plans there was on new fibre packages, but also nobody could assist me with that. Also made calls from one department to another. I am very upset as they are there to provide a service. The service is terrible.