zenka loan app

I borrowed a loan from zenka loan app 3000 and I was to pay 4170. due to 2 days late payment I started receiving endless calls from them I decided to pay 600. I checked the app remaining balance was 3570 . they called me the following day after partial payment for me to clear the balance. after the call I checked the app and was shocked the amount is back to 4170🤒🤒🤒 does this make sense?? am bored and I have decided not to pay the loan anytime soon acha niekwe CRB 😣😣😣😣