what if they say you sent them a brick in a box?
What I did was take a photo of the item, the parcel and the postal receipt and then email them it or upload it to my file server so they can view the photos.
I took photos of all the serials and I also marked the item in a few places that you wouldn't normally see and hard to get too with a code with a ultraviolet pen.
I must had done 50+ sales like this over 1 year using Parcel2go.
Only did sales like this to users with a large number of feedback.
so no proof whatsoever?
i can see the codes being useful if they return a different broken item. but pictures of the product and a package simply prove you possessed the product at some point and sent a package at some point, not the contents.