But that's still kind of a problem - what if this person sent back the Tylenol and Aleve in the unmarked bottles? Would that constitute evidence? That's a very easy package to fake and is hardly convincing. Throwing them away is a natural response when you're angry, and it wasn't a mistake because it wouldn't have mattered if he/she had kept them. Perhaps it would be more convincing if the OP used a distinctive bottle that's not easily found. Otherwise, the best thing to do is write it off, sorry, and open your packages in front of the delivery guy from now on.