Rude agent

I just received a call from a collections agent who's name is Portia Nkandlo. She called to say my personal loan is in arrears because they didn't receive payment in January. I asked her why are they calling me in June for an unpaid premium of January. She was utterly rude telling me that it doesn't matter when they call me all I have to do is make payment. All I wanted to hear is that they acknowledge the mistake and then we can continue with the payment arrangement. She cannot speak to customer the way she did with me. She was so demanding and cold