If someone received a transaction by wrong should he give it back to its owner or keep it?
If everything is clear, I'd give it back.
Your analogy doesn't hold though: think of it as funding a Bitcoin address: nobody is going to give it back to you if you lost your private key.
What do you do in daily life?
This.
If you received an upfront paid delivery while it was for your neighbor would you eat it because the delivery guy gave it to you by wrong while you know who owns it?
No. I probably won't like what they're eating. Besides, what if someone's trying to poison the neighbours?
Seriously though: here, packages are delivered to the neighbours all the time. It's normal.
~his soul will be suspended until his debts are settled
You know religion means nothing to the rest of us, right?