From
https://en.wikipedia.org/wiki/5G_NR_frequency_bands
C-Band frequencies are defined as n77, n78 and n79. The problem band is n77 which is quite a broad band, almost 1Ghz.
As I mentioned above, even though the mobile phone telecoms are brutally competitive with each other they have always centred their business around growth which also means not killing off their customers. I'm sure by their very competitive nature we will see them pursuing the FCC for any compensation they are entitled to.