Incorrect debit order, Lack of proper notice, and Unfair or unexpected billing practices

My Bill was suddenly changed from R749 to R899 , SuperSonic sent me an invoice for R749 which was due on the 25th of March, then they sent another invoice of R899 on the 22nd of March which I believe it should be for April, when I called the first person I spoke to on the 26th of March told me it was a mistake on thier side, the bill waas supposed to remain at R749 and they would escalate to the billing departmnent, nothing was communicated to me there after, I just called today (8 April 2026) and the lady told me this was communicated to all the clients ,but I never receieved the comms, she told me there's nothing she can do about it. I asked to speak to the manager and I was left hanging on the phone for more than 10 minutes. The issue is them sending 2 invoices for the same month and debiting my account with money that was not agrred on. I would like to be refunded for the R150 that was extra for the month of March as they had sent the Invoice for R749, but debited R899 for an invoice they sent 3 days before the actual debit order which is unprofessional and that's the reason I'm disputing it . The date on the Invoice is also for April not March, can this be attended to with urgency?