It seems to me. Once it has been altered, it's not the same contract previously agreed to.
I recently ran into a case at Groklaw about contracts in today's world that could apply to anyone here with contracts on Voip, wireless/cell service, internet service, etc..
From the 9th Circuit Opinion...
Joe Douglas contracted for long distance telephone service with America Online. Talk America subsequently acquired this business from AOL and continued to provide telephone service to AOL's former customers. Talk America then added four provisions to the service contract: (1) additional service charges; (2) a class action waiver; (3) an arbitration clause; and (4) a choice-of-law provision pointing to New York law. Talk America posted the revised contract on its website but, according to Douglas, it never notified him that the contract had changed. Unaware of the new terms, Douglas continued using Talk America's services for four years.
After becoming aware of the additional charges, Douglas filed a class action lawsuit in district court, charging Talk America with violations of the Federal Communications Act, breach of contract and violations of various California consumer protection statutes. Talk America moved to compel arbitration based on the modified contract and the district court granted the motion. Because the Federal Arbitration Act, 9 U.S.C.

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