Cables don't usually curl, stockinette curls all the time. It's the nature of the beast. Since the scarf is primarily stockinette it will curl. You can try blocking it, but it may not work well. Even pure wool has a hard time with stockinette. Sometimes a border helps, but it would have to be pretty wide in this case to maybe work.
BTW, don't use all caps. It's considered yelling on the Internet.