Ok
This will be a long post but i think i found a fix for this issue
I purchased an iphone 7 plus 256 gb three weeks ago
Like everyone here i got the dropped calls and GPS issues. when i left the apple store the phone did not connect to any networks. i returned the same day. They spotted the VPN slider going back and forth. They got that to strop and i was able to connect to AT&T Network. The next day i still had the dropped calls. I then went to my carrier and they notified me that the wrong IMEI was being used. Stating apple shouldve updated the IMEI when they swapped out the new phone. They swapped out a new sim and updated the IMEI. figured i was on my way. The next day i got the dropped calls and the slow GPS. Went back to the Apple Store they swapped out my phone for a new Iphone 7 Plus new SIM Card now im on my way. The next day dropped phone calls again. A Call into Apple Care Resulted in 4 Dropped calls just to finish the call. They reserved a spot for me at my local apple store and i downgraded to a 6s Plus. This made for my 4th phone in 5 Days. Obviously being frustrated over the drop calls. An apple manager told me it might be a software update that might resolve the issue. I kept monitoring sites like these looking for developments regarding software updates. I went into the apple store after seeing people saying beta updates was resolving the issue. Went to the store to pickup a new 7 and after explaining my issues to a rep he ask me what kind of case i was using? Not understanding what he was saying. He mentioned to me with the antenna shift anything metallic would cause a drop call or issue with the GPS. Hoping for anything that could work. I got a new case from apple for free and i tested the phone with the new case and im proud to say NO DROPPED CALLS or GPS.
I know it sounds silly but make sure you check your cases. After i changed cases i have not had a single issue, I'm convinced that my issue was caused by the cases i was using with my phone. Just wanted to share