403b Loan Remaining Balance Question

Hello all,

Had a question about my 403b loan balance. I tried talking to representatives multiple times and got nowhere. I took a $13,000 loan out to remodel my kitchen. My repayment method is payroll deduction and I have been matching each biweeky payment with an online payment from my checking account of the same amount, effectively doubling my payment. My issue is that I am only seeing the extra payments I have made reflected in my remaining balance, the payroll deductions seemingly nowhere to be found. Again, I took out a loan for $13,000 and even with payroll deductions AND my online payments since the beginning of September, my remaining balance is ~$11,898. I am wondering why that amount is not less given that I am matching my payroll deductions. Where is that money going? Hopefully this makes sense and thank you for any help.