Standard bank refusing me an arrangement and want to take legal actions even when I am paying the arrears monthly.

I am unfairly treated by the bank my home loan account is less than two months in arrears and owing R9000 in arrears I wrote an email a month ago informing them that I can pay R500 extra on the account to cover the arrears they responded after a month kept quiet the whole time so I paid the current amount and the R500 as per email today I received an email stating that I need to pay the whole amount and that the account is red flagged and that they are proceeding with foreclosure on the 25 of this month I,m very unhappy about this I,m being treated unfairly by the bank and they did not even respond to the email then they only came back today saying there want the whole amount I don't understand why they are refusing me an arrangement.