Horrible Service I've ever had !

I have a personal account with FNB, due to some personal reasons I stopped paying my account and it was handed over to Legal. I was then contacted by Debt In and made arrangement to make monthly payments of what I could afford. I have been paying for the past 12 months or more and my account has been updated as active and up to date on the credit bureau.

To my surprise after my July debit order my account went from up to date to 64 months in arrears. This is now affecting my credit record and I have been trying to get answers from FNB and Debt In with no luck. I spoke to an FNB employee, Thando Cele who then requested confirmation of my arrangement with Debt In so that she can escalate my query. I spoke to Debt In and requested something in writing since my arrangement was made telephonically and shock of my life I have been issued with a settlement letter expiring in 30 days.

All I want to know is what has made my account to change from up to date to 64 months in arrears between June and July 2021 even though I have paid for July as well.

I understand that I have defaulted my payments and have made an arrangement to pay off my debt but is this how you treat people ?