I bought 5 new smoke defectors from Home Depot the Kidde brand. The directions call for a mounting plate that I don't see. It could be something I am doing wrong. Even so 3 won't work I have currently have detectors because they say it is a center mount. I called Saturday 1/27/2018 and got a recording they were in a staff meeting. I then emailed on 1/27/18 and never got a response. I called Tuesday 1/30/18 and was on hold 40 minutes. Unacceptable. I will be returning all 5 later today. They need to learn to be responsive.