Cancellation of debit order

I have been trying to get me debit order cancelled since January 2020 without any success and I have not received any assistance.

I keep calling MTN to cancel my debit order for a product i do not have and every time I get told the contract will be cancelled , to date the contact is still active. I fail to understand why MTN is refusing to cancel the debit order as I have already handed the device at an MTN store in January 2020 and I was then given this ref number: IRMS 208269 and ***. I would also like to have all the money that has been debited from my account to be reversed back into my account. I would like someone to contact me with this regard.