Forget about all the scenarios about "will they catch me or not if I keep it with all the variations and angles of that sick type of thinking..." etc, etc, etc....
There is only one clear course of action and hopefully you shouldn't even have to think twice about it.
If you consider yourself as someone with moral integrity, as I'm sure you do, the only answer is to return it. Anything else shouldn't even cross your mind... ugh...well, ya, ok... that's in a perfect world... but, in our real world, a couple nano seconds is ok...

then return it... hahaha
Good karma feels good...!!! When you look at yourself in the mirror everyday and really like the person you see, life is wonderful and happy. That's a HUGE payoff...!
But then... I'm telling you something you already know... because
you are already a good person...
When children grow up, hopefully they will come to understand this philosophy, thus becoming better human beings feeling good about themselves...
Looking back over my years, 65 now, I wish I had learned this way of thinking and living a lot earlier in life. It would have saved me a lot of pain, unhappiness and been a lot easier.
Hope springs eternal, in every moment we change. Where we go and what we do with that change is totally up to us. We are truly the "artists of our own lives" and it is never too late to "change our course in a new direction"
Signed... Dr FeelGood....
Just my humble opinion...