Please change my debit order date

I have spent the whole month of November trying to get a hold of someone at FNB who can assist me with changing my debit order dates as my salary date has changed. Two weeks ago at the East Rand Mall Branch they were unable to help me. How does that make sense? They got me on the line with a bot and the bot could not process my claim. After that I have sent countless emails to tell them to change my debit date. Would you prefer that I not pay at all then? Additionally, I have asked WHY are you charging me R132 for debit charges when I already told you what to.