Q: My iMessage is not using my cell phone number and it has grayed out the phone number and only continues to use my iCloud email with iMessage. I already did the network setting reset a few times with wifi on. Please help

My imessage doesn't give me the option use my cell phone number to send and receive. I have already done a Network Reset and had wifi on. Still doesn't work. I've searched up what to do to make it work to start using my phone number to send and receive and still doesn't work. With that being said when I turn on iMessage and FaceTime again it keeps saying "waiting for activation" I already did a Network reset again for this too. I don't what else to do . Can anyone help