There shouldn't be. I originally bought the mobile phone by installment, but later I got a refund. That may be because the installment payment has been terminated, and there is no need to pay back the installments in the next few months. The part that has been returned before will be returned at one time. The mobile phone will be returned as soon as it is bought back, and the installment payment will not start to deduct money. In short, there should be no interest. If this refund is not made in time, another month's bill is generated, or it is told to return this installment normally, it will still be returned this month. If you think you have already paid it back, you don't need to pay it back, it will generate interest.