Iphone connection issues - not ringing, text fail to send etc

Until recently I’d never had a problem with any calls going to VM unless I had it set up this way. For the most part I rarely had SOS in areas I shouldn’t have but now is frequently happening. I’m only being told by TMobil support to do a master restart after verifying with them that I was all caught up on the latest updates and troubleshooting all the basic reasons why my calls wouldn’t be going through. I also have WiFi calling set up as well. I finally did a restart and the problem was fixed immediately. My problem is more than just the SOS service and calls going to VM.. I didn’t know I had a problem until my roommate came in to tell me I had a call because my phone wasn’t working! I have 3 kids that HAVE to be able to get in touch with me at all times! So what am I supposed to do, constantly do a test call to make sure it’s working?! I hope they fix this problem in their next update, I didn’t have this problem at all until this most recent update.