Amazon sent 2 of the same items…

Long story short, a while ago I bought a monitor on black friday for 72000en (Sold by Amazon). I posted complaining about Sagawa Express on my previous post and last friday, I called amazon telling about my situation then they offered to either refund or resend it and I really wanted it so I chose to resend it. Next day and the next thing I knew, the monitor came already! Thought it was masterclass japanese compensation service, opened up like it was a christmas present and played games for hours.

Next day I woke up to my apartment phone ringing and there was another delivery by Yamato, strange I thought since I didn't order anything else. Then opened my door to this delivery guy carrying a gigantic box which was another monitor. I check my emails and Sagawa Express's tracking and apparently the Monitor that was stuck with In transit Sagawa for a days was sent to me, I assume amazon didn't contact Sagawa to send the monitor back to them and they resent another monitor to me without knowing I receive the previous order already.

What do I do? Thinking of contacting Amazon back about this, but on the unethical side of my mind, I take this win and have 2 monitors or sell the resent one to cover the costs. (Basically I got a monitor for free) Any opinion and advice would be appreciated.

Update: Apparently they have no idea what I'm talking about and "Preferred" for me to keep it, so free monitor I guess.

by Juiseii