Incorrect debit order

I make payment to discovery card no later than the 25th of a month for the full amount due for the period but have still had an additional debit order alert going off my bank since January 2018. I contacted the card division and was advised to have my debit order date changed. So I completed the required form and submitted onto Discovery Card. For the April 2018 payment the payment due date as per my statement was the 02 May. I made payment on the 25th April. On the 2nd May I received an sms from my bank stating "Debit order,DISCOV CRD?/cardnumber and amount reminder please fund your account." Highly frustrated at this point I sent an email to Discovery Card immediately with this information stating I made payment and yet debit orders are attempting to go off charging me bank fees which are inapplicable. I requested on this mail for a manager to assist with my query. On the 09 May I realised I have not yet had a response as per their auto reply which states "Your reference number is: ********** 00 and you can expect a response to your enquiry within two working days." So I send them a response on my initial mail stating that I have not had a response. I did not receive an auto reply this time which concerned me as it seems like a rule was set in to ignore my email content. I called the called centre and spoke an agent named Landi Khanyile, She tried to assist me and asked me to call back later in the month ensure that the same thing does not happen. She said please hold while I make a note, I was on hold for more than a minute, she comes back apologising for holding. I then asked her why did you put me on hold, She said I asked someone for assistance on this. I then asked why did she tell me she was making a note but instead she seeked advise. At the end of the call as I was getting no joy from her, I asked to speak to a team leader, she said she will get one to call me back. I asked by what time would they call and she responded before lunch the same day. To date which is 4 days later I have still not had anyone from Discovery Card calling me or attending to my email. Since my initial mail to them, today is 11 working days and nothing has been done.