Bul**** for trying to change debit order date

My debit date is the 01st of the month but for some odd reason discovery only debits after the 01st mostly on the 2nd. I had a chat on their website on the 01st midday to change my debit order date to the 28th as i cant have the inconvenience this is causing me. The lady on the chat advised if the debit order for April does not go through in 24hrs she will force push it, i agreed and we changed the date to the 28. 2nd Apr im debited twice R4K unbudgeted. I called Discovery today at 10:34 the call was for 18min 43 seconds, to ask what is going on and I was not assisted at all. She said the reason Im debited twice according is because I changed debit order dates. She said when you change the date you must pay the 2 months in advance and there is no other option, either I take the double debit or I change back and endure the inconsistency of being debited after the 01st. Trying to understand the logic behind paying 2 months in advance was useless, she kept on saying thats how it is, and there is nothing she can help me with. She could not help me with reversing the 2nd debit order because it takes 3 days before they see it on their side so I must wait. The only option i was given was to change back to the 1st and wait 3 days for the refund to be send for processing.