FNB 24 month Early Settlement

Good Day,

I took a 24month contract with FNB for a laptop in 2017, with a monthly payment of R 649.00 . I have 2 months left. I would like to settle the outstanding amount early . My current outstanding balance is R 1298 but when i click on the settlement tab it say i need to pay approximately R 2800.00 . How the does this work? This is product which is interest free and has fixed term. If they don't offer a discount for settling the outstanding amount earlier then surely the settlement amount should not be more that what is due. I want some urgent assistance but every time i call the call centre I get cut off.