Can't display the result

Hi, I have an equation and PMT function. But the result didn’t display

Here the formulas

(function calculateInterest( totalAmount, numberOfPayments ){
var interest = 0;
var totalAmount = fieldname1;
var numberOfPayments = fieldname22;
if(5000<=totalAmount && totalAmount<=12000)
{
if(numberOfPayments == 9) interest=0.994;
else if(numberOfPayments == 12) interest=0.9351;
else interest=0;
}
if(12001<=totalAmount && totalAmount<=30000)
{
if(numberOfPayments == 9) interest=0.9383;
else if(numberOfPayments == 12) interest=0.917;
else if(numberOfPayments == 15) interest=0.8607;
else interest=0;
}
if(30001<=totalAmount && totalAmount<=60000)
{
if(numberOfPayments == 9) interest=0.9383;
else if(numberOfPayments == 12) interest=0.8988;
else if(numberOfPayments == 15) interest=0.8429;
else if(numberOfPayments == 15) interest=0.7901;
else interest=0;
}
return interest;
}

function calculatePresentValue( totalAmount,downpaymentAmount ){
var downpaymentAmount = fieldname2;
var presentValue = (totalAmount- downpaymentAmount);
return presentValue;
}

function PMT(totalAmount,downpayment,presentValue,interest,numberOfPayments ) {

var monthlyPayment = PMT( interest, numberOfPayments, presentValue )
var fv=0;

if( ! fv ){ fv = 0; }
var PMT= ( interest * ( presentValue * POW( (interest +1), numberOfPayments ) + fv ) ) / ( ( interestRate + 1 ) * ( POW( (interest +1), numberOfPayments ) -1 ) );
return pmt;
}

function calculateMonthlyPayment( interest,numberOfPayments,presentValue ){
var monthlyPayment;

return monthlyPayment = CEIL(PMT(presentValue/(1-(1/(1+interest/12)*EXP(numberOfPayments)))/interest/12)/12);
})()

http://www.homecredit.ph/2177-2/

Please try it to Mobile product

https://wordpress.org/plugins/calculated-fields-form/