Monthly principal of 36 installments: 15000/36=4 16.67.

How much principal was repaid during 14: 416.67 *14 = 5833.38.

The remaining principal payable is:15000-5833.38 = 9166.62.

Interest: (900-416.67)/15000 = 3.22%

But as far as I know, this 3.22% is not entirely interest, it includes insurance and other services. You need to know what fees there are besides interest, and you won't know what the real interest is until you deduct them.

My personal suggestion is to prepay, because if you don't prepay, you have to pay back to 900 yuan every 22 months, one day 19800 yuan. Of course, it depends on your present situation.

The customer service told you that you still need the principal of 1074 1, which is 9 166.62, and you also charged some other service fees.

If you want to continue to pay monthly, you can tell the customer service to cancel the insurance and other expenses.