Unable to make or receive phone calls because of poor service

For the past couple months, ever since the "upgrade" happened in my area, I've been having absolutely terrible call quality. I can't hear them, they can't hear me, the calls are constantly dropped. It's mostly in the zip code where I work, when I'm at home it's not quite as bad. Regardless, this has interrupted a lot of very important business on my end and I'm considering switching cell phone providers because of it. My girlfriend has Verizon and hers is working just fine. To be clear, my phone does say it's connected. I can access the internet, send texts, etc, but making phone calls is basically impossible. I can't even reach my own voicemail.

I did a network reset, I went through all the other silly recommendations, it's still not working. I need a solution or I'm forced to change providers.