I ordered an iphone 6 plus but later switched carriers what should i do?

I had ordered an iphone 6 plus in verizon which was going to get shipped to my house

I went to cancel the shipment before it was even shipped out and they told me that they were unable to cancel cause it hadnt been shipped

They told me i would get a email comfering that i ordered it and if i still wanted it which i never got

I switched over to tmobile about a week ago and the phone arrived yesterday which my bro signed for

What should i do? Just take it back or what? And will i pay a restocking fee?

Just return the phone and ask for a refund