Unauthorized debit orders

What's the point of having debi check approval ****ion if debit orders can just go off my account even after I decline and others that I did not even approve. A few months back I got a debi check approval for Vodacom for about R200 and I declined and called standardbank to make them aware of this,a month later R789 went off my account without any debi check approval request again,I called Standardbank to reverse and asked them to explained how a debit order goes off without any debi check approval the consultant had no answer and promised to revert back to me and to date I'm still waiting. Just yesterday R3457 was debited from my account by the same Vodacom,I guess my money is not safe with standardbank. At some point the standardbank consultant advised me to go Vodacom, I'm not sure why as I have never had any contract whatsoever with vodacom neither did I use the network