shēnqǐng tuìkuǎn hòu, bǎoliú sān yàng dōngxi: zhīfù jìlù, xiǎopiào huò dìngdānhào, diànyuán gěi de tuìkuǎn píngzhèng

申请退款后，保留三样东西：支付记录、小票或订单号、店员给的退款凭证。

After applying for a refund, keep three things: the payment record, the receipt or order number, and the refund voucher provided by the staff.