NEDBANK - Extra Debit Orders Than Arrangements

X5 debit orders went off my account this month(April 2020). This started by February 2020 when they double debit ordered my account and I called them and they said I must make a new payment arrangements and the escalated to March 2020 and I also called them, they couldn't say the problem, but was promised for refund in 48 hours, but nothing happened in five working days, I called my bank and did reversal myself. Now this month(April 2020), they debit x5 times and when I called now, they say they will refund me in 48 hours, but they won't refund me all extra amount only about 60%, I'm really not happy, because we had an arrangement amount. WHY CAN'T THEY STICK TO THAT.