https://arstechnica.com/tech-policy/2020/02/t-mobile-claims-it-didnt-lie-about-4g-coverage-says-fcc-measured-wrong/

T-Mobile says the Federal Communications Commission screwed up 4G measurements in a report that accused the carrier of exaggerating its mobile coverage. The FCC report "incorrectly implies, based on a flawed verification process, that we overstated coverage," T-Mobile said in an FCC filing Monday.

The FCC staff report, issued in December, found that Verizon, T-Mobile, and US Cellular exaggerated their 4G coverage in official filings. As the FCC said, "Overstating mobile broadband coverage misleads the public and can misallocate our limited universal service funds."