MWeb Debit Order

I stopped my debit order with MWeb in April 2019. They are changing the reference numbers, and the money is still going off of my account. I have no contact information to report it to them. Every time I stopped the debit order, they change the reference number every time after stopping the debit order, it's like playing musical chairs. I left the country in 2018, have no physical address in South Africa anymore, and do not have a Mweb email address, but they have taken money monthly from my account for the last 48 months. How can I get in contact with their billing department, please?