Cancellation processsed 5 months ago but they still want to Debit !!!!@

Seriously I'm being taken for a ride by Gym Company. I send through an email 4 months ago requesting for cancellation due to relocation. I was made to sign a cancelation form which i then submitted to the account. After finalizing the cancelation, I was then told that they were going to debit 3 months after processing the cancelation. To my surprise, after 3 months of debit, Gym Company still calls to tell me that I owe R399. How am I still owing if I already processed cancellable 4 months ago. If this matter is not resolved, I will be escalating the matter for legal intervention or with the Ombudsman. This is total bull****!!!