Incorrect Billing

I am FRUSTRATED dealing with Vodacoms call center for an issue that I'm not responsible for.I called the call center on 23 March advising my debit date needs to change from the 24th to the 26th monthly and the agent i spoke to assured me that this new date will only kick in April which i was satisfied with.I was then double debited,on the 24th and 26th March for the same amount.I queried this with the call center and the agent acknowledged that Vodacom has made an error and i need to call the accounts department which I refused to do as the error was not on my part.The manager on duty-Tsepho Mosese-logged ticket #*** to accounts department and the money was deposited back into my bank account the next day.A few days later i get a sms from vodacom that due to a missed debit on 26th March,my account is in arrears and penalties apply!On 02 April a very rude Megan Lundall at accounts advised that she will investigate to see if i am \liable"for the penalties but no feedback as been received to date.A few days later"