Engaged 3times to correct the bill but still it's incorrect!

"To err is human to forgive is divine" but the problem starts when you are made to feel stupid. Early this month I received my statement and noted that my bill was extremely high. Reached out to the call center where I got assisted by this warm & friendly agent. The matter was "resolved" earlier than eta, if that's not excellent client experience then I don't know what it is. The feedback provided was vague so calmly reached out to the call center again. Once more got through to a different but exceptional lady who logged my request now for the 2nd time. A few days later got a call from another warm-hearted lady who tried explaining but despite me trying to explain to her that the final billing is not correct she didn't get until now my debit order runs and boom I'm debited with an incorrect amount. So my question is did I waste my time 3times to engage with Vodacom? How was the error not picked prior to the statement being sent to me? Why was no one interested that come billing date the correct figure is debited? Doesn't Vodacom take their customers serious or it depends? If it depends, it depends on what exactly?