Makro/RCS credit account is debited, but still you expect another payment!

I've been debited by Makro on the 28th May for the amount of R275.46. This amount is less than what you usually deduct from my account, then during the month you start sending me letters saying there's an outstanding amount! How can you expect a payment when you've already debited an amount!? Why don't you just deduct the full amount once? Instead of turning this into a problem for me. I'm sorry, but your company can't just chop and change your financial protocol to suit yourselves. This is hardly fair on the consumer. I first e-mailed Makro and was told that they don't have this info. I was then directed to RCS services who haven't rep**** to my email since June 14. Please sort this out!