According to Chow Tai Fook's policy, the invoice of the purchased platinum necklace was lost and it was impossible to exchange it for a new one. Chow Tai Fook will charge a certain depreciation fee regardless of whether there is an invoice or not. Losing the invoice will only increase the difficulty of replacement. According to the regulations, if there is no invoice, you will have to pay an additional 7% depreciation fee, plus a processing fee of 10 yuan per gram.