Twin Serta Mattress - $300

Purchased from Sam’s Club for $349 plus tax the weekend before Christmas for my daughter’s new bunk beds and it is too thick for her to sleep safely on the top.
I clearly did not read all of the bed instructions.
It has been covered with sheets and a comforter since being removed from the packaging.
She has laid on the covered bed to watch tv but has not slept in it.