Cancel the debit order

I was thrilled to join and enjoy the benefits of the debit order hence I decided to approve of it. The only problem is that the benefits have not come into fruition ever since I have been shopping. But even so, a sum of R251.00 was still taken out from my account. I would like to cancel the debit order since I'm still a student depending on a monthly allowance to make a living everyday. I have been sending emails to Clientelè about drawing out but I have only received an automated response.