VODACOM BAD SERVICE

I called Vodacom account department on the 02/08/2024 to activate the debit on my account, because I had to make cash payment into the shop. After giver the consultant all my bank details my application was declined for debit oder... My surprise this morning I wanted to purchase a flight ticket online and I discovered that Vodacom had deducted my account on the 07/08 for the same amount I made an EFT. I called Vodacom this morning and was told that they couldn't revers the money they deducted from me, I need to call my bank and block or reverse the deduction. How could Vodacom go ahead with the debit order while we did not agreed on it and I already make the payment????