Phone Not Accepting Calls

Hi! To sum it up quick, my phone straight up refuses to let most people call me. Some of my contacts can call me, but other contacts can't, and numbers outside of my contacts can't at all. It used to at least send them to voicemail, but lately it's saying my phone is completely out of service and I'm running out of ideas. Everything is paid for and in service as far as I know, my phone just won't let people call me. I can call them with no issue though!

I used to have that AT&T Call Protect app and had it set to totally block numbers outside of my contacts, but then that app went out of service before I could cancel that, so I wonder if it's still somehow in effect? 

If it matters at all, I have a Samsung Galaxy A71 5g.