Home loan agreement total amount miscalculated

I took a home loan with Nedbank in 2007, last year I requested another additional loan of R80 000. At the time of the request the outstanding amount of the loan was R201 382, check part A : Loan Amount on the contract attached. When you add the two amounts the new total loan amount should be R 281 382, but somehow on the contract the total amount is R318 333 which was miscalculated, please check PART A:LOAN AMOUNT on the agreement attached. The amount added is extra by almost R37 000. I went to the Nedbank branch to explain to me why the addition, they could not explain the extra R37 000, they requested that I call the home loan department. I called home loan department, but unfortunately the consultant did not help me, he told him on his side everything is correct, I even suggested that I send him my contract. All I want is my agreement to be amended to the correct amount of R281 382.