Wow, there are four distinctly different problems here:
My MOTOG4 is saying that the San Disc SD Card is missing. This is often fixed by removing, wiping the contacts with alcohol, and replacing the SD card.
The phone is restarting itself on a regular basis. This has been known to be cause by an app running amok. Common culprits are Facebook and Facebook Messenger. This is generally identified by operating the phone in Safe Mode to see if the phone spontaneously restarts when downloaded apps are disabled.
I cannot send texts or make phone calls. This is usually fixed by running through the troubleshooting steps in this document:
Make and Receive a Phone Call
- It says I do not have a preferred way to send SMS messages. Your default messaging app should be Google Messenger which is now called Android Messages.
The only element I can think of that would be common to all of these problems would be the cache. Instructions for clearing it are here:
Clearing the Cache