Debiting Account that is in Credit

I paid my account on 23/03/2018 before to avoid having any debit orders going off my account, which was only to be debited on 03/04/2018. However someone at Vodacom just decided to debit my account on 04/04/2018, even though it was reflecting a credit. Now I am expected to wait up to 2 week for a refund for their mistake, in these economic times this is not acceptable, as every cent is allocated without having a young call centre agent being arrogant about the nature of your complaint.