Before the Federal Communications Commission (FCC) and the U.S. Department of Justice (DoJ) approved T-Mobile's $26 billion purchase of Sprint, the two companies were full of promises about how their merger would encourage, not stifle, competition. Along with pledges to maintain their various prepaid brands, the companies said they would encourage MVNOs to use their networks.

Now, both government agencies have blessed the deal, and the companies are awaiting judicial approval. Sprint is shuttering Virgin Mobile, one of the brands it said it would maintain. The carrier is in the process of migrating most of its Virgin customers to Boost Mobile, which is set to become part of Dish Network if and when the T-Mobile/Sprint deal closes. Boost founder and former CEO Peter Adderton recently told Fox Business News he is very concerned about that company's future with Dish.

"There's no way in the world that they can maintain the MVNO agreement that they have today and be able to keep the 9 million customers," Adderton said. "Two and a half million or so at least are just not profitable customers." Adderton said Dish has made no specific pledges to retain Boost customers or employees.

Sponsored by EQUINIX Equinix Whitepaper: Enabling the Mobile Ecosystem Platform Equinix™ provides the ideal solution for regionally distributing high volumes of traffic closer to users and applications in order to ease congestion over backhaul lines. Download this whitepaper to learn more. Download Now

RELATED: The skinny on the T-Mobile/Sprint/Dish deal

Other MVNOs that rely exclusively on the Sprint network include Altice Mobile, Tello Mobile and TextNow. After the merger, these MVNOs will presumably do business with New T-Mobile, the merged company. The company will also support T-Mobile's existing MVNOs, as well as Dish, which will get access to New T-Mobile's network for seven years if the deal closes.

Back in 2018, T-Mobile told the FCC it would offer "attractive plans to MVNOs" in order to fill its "expansive capacity." This was before the company knew it would be sharing its spectrum with Dish.

"There are no provisions to protect anybody besides Dish and Altice," noted analyst Roger Entner, founder of Recon Analytics. He said the other MVNOs could potentially be dropped or face stiff price increases. MVNOs pay carriers for access to spectrum, and the prices they charge consumers are closely related to the prices they pay for access.

Some of the most aggressive pricing in the market comes from T-Mobile's existing MVNOs, like Mint Mobile, which is owned by Ultra Mobile, also a T-Mobile MVNO. Mint Mobile is working closely with Amazon, which is selling the service and including Mint Mobile promotions in unlocked smartphones it ships to customers.

Amazon was said to be a potential buyer for Boost Mobile before Dish agreed to buy it. If the online retailer has wireless ambitions, it could step in as a partner for one or more MVNOs if wholesale spectrum prices start to escalate after the T-Mobile/Sprint deal closes.

Another tech giant with potential wireless ambitions is of course Google, which has MVNO deals with both T-Mobile and Sprint to support its Google Fi service. The company has not marketed Google Fi aggressively and its long term plans are unclear. But if Google wants to stay in the wireless business, it is one MVNO that almost certainly will not be priced out of the market.