I sometimes wonder where people come up with these "laws".  Federal law specified 8 am to 9 pm your time any day of the week.  State laws vary, so unless your state law specifically says that (which I doubt), they are within their rights to call.  Now, since this is a organization of criminals trying to steal your credit card information, you also have to realize that by definition, criminals do not obey laws.  If they did, there would be no need for cops, judges, courtrooms, lawyers, and prison.