Fnb connect

I took an fnb Sim contract and chose the debit order to be the last day of the month. Since February they have been deducting money on the 28th. I called to enquire they admitted to the mistake and agreed to fix it but it's continuing. I then decided to move the debit order to the 1st of the month. They now double debiting my account. What I find Strange is you can't query the debit like all other debit orders. FNB connect is a ****.