Ok so I've had issues with issues with coverage where I work. I can't say enough good things about T-Mobile in terms as a carrier though. I generally get service everywhere I go for the most part with the exception of my office (and sadly they don't offer WiFi in my building). So ever since I switched and I discovered this lack of coverage I've been on a quest to find out how I can get cheap/free WiFi/Cell Service to augment my coverage. I know that T-Mobile has WiFi Calling which is very useful when you have access to free WiFi. So after some research I came across FreedomPop which advertises "free" cell service and data plans. I'm not trying to advertise for FreedomPop (and they are pretty sneaky when it comes to dinging you with extra "services" so you have to pay extra) but I managed to acquire a mobile hotspot through them which operates on the Sprint network. My only requirement is to have enough service that if I don't miss an important call (being married with three kids puts this as a priority in my book) or text while at work.
Well the mobile hotspot works great and so far the service has been pretty much free (I disabled a lot of the extra services and I had to pay an activation fee but other than that I get 500mbs free every month) it didn't allow WiFi Calling. I even tried other mobile hotspot devices and other WiFi hotspots with no issues. For some reason I could never make WiFi calls on any devices while connected to it (and I've tried a couple different phones). Fast forward a few months and T-Mobile rolls out the DIGITS program (a program I wanted to try when it was in Beta testing). This program is in some ways better than WiFI Calling because it has the option of using cellular or data to make and receive calls. So if I connect to this device and make a call using data through the DIGITS app I have no trouble with calls or messages. I need to test it out some more but I really feel this program is in some ways superior to WiFi Calling simply because not all phones have that capability. Add in the fact that you can use DIGITS on a computer and even if you're in a place that has no service T-Mobile seems to have given us the most options in terms of increasing our service.
I hope this helps anybody who is in a similar situation as me. I've tried so many options and to have a free workaround to this issue is great (I have a cellspot but no place to use it where I work). If anybody wants any further information let me know and I'll be happy to provide more information.