The second-hand mobile phone I bought at Idle Fish was cheated. He only gave me the mobile phone box by express delivery, and only signed it to bring you the package by express delivery, without giving me proof. What should I do? If you had opened the parcel immediately after signing for it and inspected it on the spot, you could have asked the courier company to issue a certificate and then complained to the idle fish. Now, that's trouble. There is no evidence, so you can only talk to the courier company and ask them to give you a certificate. Otherwise, there is no way.