1) USCC and AT&T have the band-12 (700 MHz) licenses in the Springfield license area.
2) T-Mobile won 15x15 MHz (3 blocks) of 600 MHz in the recent auction for that area. Bad news is that it may be 2020 before it's actually available because all the TV stations on RF channels above #37 have to be moved. That includes WRSP, WCIA, WICS, etc.
3) US Cellular has 10x10 MHz of 700 MHz in the market but does not actually serve Springfield.
I take it you don't have access to WiFi in your office?
Doesn't look good.
Unfortunately the Wi-Fi is shared with a lot of people, not only is it fairly slow but disconnects often to make sure people aren't clogging up the bandwidth.
Looks like I will have to go with at&t or Verizon for a little bit until 600 is up.