PayJustNow always ducking up not the first time.

I missed a payment and before the seven day period made sure the amount was in but still the befit order did not go off to my surprise my installment due is now R583.33 instead of R333.34 how is it that I owe a whole R145 more??

I am ****ing ****ed fix amount so that I can pay because I am now paying bank charges for debit order bouncing!!