Which evidence should I provide to prove that the contents of my parcel are incorrect?

If you get a parcel that is intended for someone else, then you shouldn't use the return label. Bring the parcel to a Post Office. Tell the counter clerk that the parcel was delivered to the wrong address. We will make sure that it is delivered to the correct address.

If the contents of your parcel do not correspond with what you ordered, then you must contact the original sender of your parcel. Ask him/her to send the correct parcel. You will usually be asked to return the incorrect parcel first. If the sender offers you the option to return your parcel, then attach the return label on the parcel and send it back. The return label is in the package, or you can download and print it from the sender's website or from an e-mail from the sender. If the sender does not offer any return options, then you can purchase a shipping label. Attach that on top of the shipping label of your original parcel and bring the parcel to a Post Office, Post Point, Parcel Point or Parcel Locker to send it back.

Some online shops allow you to indicate that you will be returning a product or item. Be sure to do that so the online shop knows that your return shipment is coming. Online shops that do not offer that option should be contacted to warn them you will be returning your parcel.