Unable to dispute debit order

Dear team, i am very upset with the fact that i cannot reverse a debit order for the second time and this is because i send numerous mail to close/block the debit order for Afrihost. They keep deducting the an amount of 549 rand. This month the money got deducted again even though i dont use their services and have requested for cancellation. Last month i was helped and in these though times deducting such a large amount is impacting my monthly finances. I contacted the helpdesk true the fnb app and i was told the bank does not reverse debit orders anymore. Can i please get assistance on this cause this is impacting my finances and also since when do debit order no longer get reversed. afrihost debit order 549 rand Also i want this company blocked/stopped from debiting my account any longer