woolworths is messing up my credit score whilst paying them

I have an account with Woolworths which I'm paying monthly. I lost my job some time last year, I informed them and made an arrangement to pay what I can afford at the moment. I continued paying that amount. on the 26/07/2024 I paid an extra R500 to my debt thinking I was doing a right thing because I had money that day. To my surprise early this morning I received an sms stating my account has been handed over. There was never a communication to say because I'm paying less than my installment this would happen. I even regret paying my extra R500 whereas I have a debit order that goes off to woolies every month. I doubt if a correct process was followed here, I'll do my research. This is so unaccepted.