How would that work? I don't remember ever getting back a copy of a credit card agreement after I sent one back. I'm not even sure I've sent something back. Isn't that all on line now?

Just add the following: "Granting the account is considered acceptance of the terms."

I don't think it would have as much strength as having actually signed document in hand.

Get a notarized copy of the agreement, then take them to court, then ask them to produce the original.

If you're really lucky you'll be able to add a fraud claim as they forge your signature on a unmodified copy of the agreement.

Whenever you deal with credit card companies, banks, etc, you should always make them reproduce the document.