Debit order date

When I took out my contract with Vodacom I asked for the debit order date to be on the 25th of every month and they decided on their own to debit the last day of the month and they have been lucky to get their money on their nominated date. Unfortunately last month the debit order bounced. mind you the debit order is only R135 so I got charged by my bank and Vodacom is also charging an additional R100 so in total I have to pay 3 times the amount that I usual pay just because you failed to debit on the day I requested. I have since changed the debit order date but I want the R100 to be credited and the R110 that fnb charged me to be refunded to me after you have listened to contract call.