Won a brand new iPhone 6s in a competition but want to return it?

Hey everyone,

So basically I won an online promotion from a company I am close too and the prize was an unopened, brand new iPhone 6s 32GB Space Grey. I have received the prize. They ordered it online through the Apple Store and directly put my address and phone number as the order details. My question is, can I go to any Apple Store Retail and ask to return this item as it has not been 14 days, it's unopened and it's my address and phone number on the record? Any help will