Hi Valued Customer,
We're sorry to hear that topper hasn't fully expanded! Sometimes the foam gets "stuck" and it needs help. Keeping it in a warm room can help with that. You can also walk or crawl along the topper for a few minutes at a time throughout the day, as that can help break up the air pockets in the foam. If that still doesn't expand, please reach out to us at info@linenspa.com and we can help you out.
Thanks!
-The Linenspa Crew