Payment interest charges

Once again, after a lot of emails and communication, homechoice still tell me that after I make an EFT (internet) payment std bank is still charging me an additional R7. 40 per payment, keep in mind that I already pay separate bank charges on my own bank account, why deduct a R7. 40 for every payment, honestly, I hope everyone reading this could realize the endless drama they will have buying from them on credit. I honestly wish I could add the emails they sent me. All this just because I am making EFT payments instead of them adding a debit order to my account. I also heard from someone else they deduct dubbel payments the main reason they don't have my banking details to add a debit order to my account...