Nedbank loan

So on Saturday i app**** for a loan for 72800r, on the app it shows the interest percentage and the installment to be paid monthly, now upon receiving the actual statement of the total costs. Amount payable to nedbank in full is R159878. 40. Meaning i will pay Nedbank 87078.40r extra. How on earth did they reach such a ridiculous amount. The interest is way above the money i borrowed which i assume it is 100%+. Is this even legal? Please dont take loans with nedbank they will reap u off. They cant even calculate how they got to that amount