Mfc debit order harassment,

I have mrc finance debit order going 9f my nedbank account on the 22 of each month. For April they decided to debit on the 21 saying they have the system payment as 21. The next day 22 I received 3 calls , emal 2 sms that my account is arrears, not specific to which month in particular. So I called my banker and she said but there's a debit or manded that is the system it went out on the 22. Today the 23rd they are siting ignorance as if nothing happened and no call no letter yo apologies, instead they told the banker it was after a day, which is not true. It was in less than 24 that I was dragged and harassed , the letter indicating that I have been handed over for an account in arrears which was just utter nonsense. Am yet to receive feedback in writing as I requested. Mfc just went silent.