Trying to stop a debit order with no luck.

Hy it's been days since trying to cancel the debit order I have with the company with no luck, they keep telling me that it doesn't appear on their system,but it appears at capitec,imagine R1950,00 every month.all I need is for them to stop their debit order on my account but they are giving me run around, claiming they deleted it,I'm starting to believe that it's a ****.