What am I being charged for

I am truly disappointed with the way telkom handled my account I recently changed banks and and closed my old one I contacted telkom in time to update my banking details but was told that this new bank account must be three months or older before they can update my details to it Such an inconvenience as other places updated with no hassles The issue here is I was told to eft the installment 10 prior to the debit date where I would get the money for that beats me because I would not be paid yet. I went ahead and transferred the money on pay day but they went and debited money in my old account and of course there was no money Now im being charged 200 for a bounced debit order but I did my due diligence in informing them of the changes This is unacceptable