No assistance from ABSA vehicle finance

I have made several requests via telephonic calls and emails requesting to change my debit order date for my vehicle from the 17th to the 1st of every month, it seems as though I'm getting nowhere as ABSA vehicle finance had responded to my request with a letter statsting that the debit order date has changed, it is the 6th of May and the debit order still has not gone off so I have to wait until the 17th again this is really frustrating as I have had countless issues when requesting any assistance from the vehicle finance department