iphone SE- calls going straight to voicemail

So, I upgraded to an iphone SE and everything works great on the phone except calls go straight to voicemail. I have spent the last month dealing with this issue. It is not a carrier issue because I switched back to my old iphone 6s plus and I get calls just fine. It has been sent to Apple twice for repair and they keep sending it back saying they can't duplicate the issue. I have been very disappointed with Apple as I have been getting the runaround. They set me up with a call this Tuesday to talk with engineering to have them look at the problem. Howver, the last time I did that I got disconnected. Anyways, it has been over a month and the problem still isn't fixed. I'm hoping the problem gets fixed Tuesday, but I have lost my faith in Apple. I of course, have tried everything. I have spent hours on the phone and chatting on the computer. Does anyone else have this problem? I feel like I'm stuck with a faulty phone.

Thanks!