Only retentions can order a celfi for you.
There is also qualifying criteria that must be meet before you can get one. First you must be an A or B credit class, second you must live in a stand alone house, no apartments or condos, due to 911 location issues that could mess with another persons emergency that tmo would be held liable for.
Also the celfi doesnt boost your signal it only expands the signal you already have, this is not a femtocell its merely a signal repeater to expand throughout a household.