Rejected debit order and billed more by telkom

It’s only now that I believe that Telkom is ****ming consumers.. debit order got rejected on the 25th and paid it on the 1st and now I’m being charged extra R204 as if I’m taking up a new payment whereas I’ve been using them for more than 2 years couldn’t they add their arrears or cancel data for the following month since I’m on month to month contract..