User blog comment:Amras15/My free unit still isn't in my gifts?/@comment-26332895-20151214194458

As quoted form http://forums.gumi.sg/forum/news-boards/262878-reminder-unit-of-choice-entry?p=265288#post265288

We would like to remind everyone of your Unit of Choice selection. If you have reached day 30 for our Anniversary Login Campaign [or will be able to reach Day 30 by the end of the event period which is on December 22, 2015 23:59 PST], kindly make sure to register here - http://goo.gl/F9GpEb.

• The lowest evolution of the unit you chose will be sent to your Presents Box a week after the event ends.

Bolded are what's important.