Apple returns/refund help page:

Items purchased at the Apple Online Store that are received between November 14, 2018 and December 25, 2018, may be returned through January 8, 2019. Please note that all other terms and conditions provided in the Apple Online Store Sales and Refunds Policy are still applicable with respect to such items purchased. All purchases made after December 25, 2018 are subject to the Standard Return Policy.

Good to know.