Authorized Unication Dealer
(e.g., "us cellular g3" as in a third-generation generic device or a typo), let me know and I can clarify.
If you’re trying to use a U.S. Cellular LG G3 today, you might get limited GSM/HSPA service on T-Mobile or AT&T MVNOs, but LTE compatibility will be poor, and VoLTE likely won't work.