The argument is that because Frontier said a thing several years ago that thing represents a binding contract, a mandate that cannot be overridden even by the parties who initially signed the contract. Whether or not the offer that was made and the act of taking up the offer actually constitute a 'contract' of any meaningful sort is another issue.
But the main thrust is that it doesn't matter if conditions have changed over the last three years, or whatever; it doesn't matter whether the parties involved have now changed their minds. What was said then is now and forever inviolable writ and, no matter what the changes or disadvantages that have since or may still come to light, the original terms cannot and must not be altered lest the entire concept of trust itself is irrevocably destroyed.
Actually, that...
Hmmm.
No, sorry. Carry on.