My phone will not receive phone calls but it allows me to make phone calls completely fine.

You need to work this out with the carrier. See if this helps: https://support.apple.com/en-us/HT204027

If the call is going straight to voicemail, I would discuss it again with the carrier. That is not a phone error, that sounds more like a carrier error. They are the ones that control if you have the ability to receive calls, including call forwarding and conditional forwarding.

I agree with Chris. If possible, you want to talk to upper level tech support, not just the tier 1 folks who are really just regular customer service. They're generally great at the common stuff but, when it gets weird, you need to escalate.

Then the next step would be to get an appointment at an Apple Store for an evaluation.

What happens if someone calls you? Do they get your voicemail? Have you checked to see if Call Forwarding is activated?