I Googled a bit and found this FierceWireless article from last year on the prospects of what might happen for Shentel:
https://www.fiercewireless.com/wireless/shentel-carrier-at-crossroads-sprint-and-t-mobile-merger
Pertinent part:
First, Shentel’s Earle MacKenzie said, Shentel cannot file an injunction to try to block the merger. If the merger is approved, the combined Sprint and T-Mobile—generally called New T-Mobile—will have 60 days to decide whether it wants to purchase Shentel’s wireless business.
“If they do decide to buy our wireless business, there is a formula that you provide to our shareholders, a very handsome return. If they choose not to buy our wireless business, Shentel will remain an affiliate of the New T-Mobile and for the next 180 days, we have the option to acquire the T- mobile customers and that work in our 7 million POPs service area at 75% of the value of the customers and asset as determined by the merger value,” MacKenzie said during the call, according to a Seeking Alpha transcription of the event. “If we can’t finance the purchase, then the New T-Mobile will finance the purchase at their cost of capital for up to five years. If Shentel decides not to buy T-Mobile network and customers, then the new T-Mobile must turn off the T-Mobile network that overlaps Shentel within two years.”