Account in areas

A month or 2 ago I made a payment via EFT ( as I normally do) but this time I did it earlier than other months which was the 7th. Later that month I received numerous messages that I need to make a payment which I obviously ignored because I had paid. Later on I received a call telling me that my account was on areas, I asked about the payment I had made and I was told they could see it but the system doesn't know if it's the installment since I paid early. They then told me they will try and fix it. The most irritating part is that I've just received my credit report it has dropped because of this💔. How can one make a payment ( which was even more than the installment) and the account still reflects as of it's in areas? This doesn't make sense at all. I'm so ****ed.