The "Legal Guys" on CNN took up this case. Richard Herman said (even warned) that "non disparagement clauses" are enforceable but that the consumer would win this particular care because the company put in the clause after the fact. Avery Fisher and guest attorney Paul Callan suggested that, even though non-disparagement can be put into a contract, this was obvious a contract mad ein bad faith and that courts would not honor it.
CNN reported that customers found that the company could not be reached by phone.
CNN also reported a similar "fiine" with a real estate contract in Florida. But so far, charging a "fee" instead of suing has been very unusual. It sounds like a frightening idea.