Bad service

I changed my debit order date and the consultant did not explain to me that even though the date is changed they will still debit on the initial date and the new date! When the debit order bounced I called to ask and that’s when they explained to me. And she further said they will charge me extra because the debit bounced. This month I’m charged double. I called twice to get clarification on how is it my fault to all of it and why am I being charged!! Never again with telkom!!!