[mothered]

I was thinking about doing the dna

Check If an OTP will be required on delivery.

The dna may not work due to the weight

The weight Is Irrelevant.

You're purely claiming nonreceipt of goods, hence It doesn't matter how heavy It Is.

When it comes to the wrong item sent, say I do paper to one address and the gpu to another both in the same city and I send them the paper back in place of the gpu can they tell that the paper was shipped already to an address in the same city?

Simply say you've received an Incorrect Item to what was originally ordered. The next course of action will be based on their reply.

I suggest you fully familiarize yourself with the WIR method prior to moving forward. Check out the articles on my blog on how It's done.