India, July 19 -- T-Mobile is facing fresh questions after responding to an FCC complaint over its decision to move some longtime customers off older plans. The complaint was filed by California customer Alex Gerwer, who says the company promised his internet price would never increase. The FCC gave T-Mobile 30 days to respond, and the carrier has now submitted its explanation. However, Gerwer says the response did not answer his main concern. The dispute is centered on whether T-Mobile's plan changes go against earlier price lock promises made to some customers.

According to PhoneArena, T-Mobile told the FCC that it "appreciate[s] the opportunity to provide additional information."

The company said some of the affected plans were intro...