This number comes up as Nationwide Processing.  This is a scam collections agency called Credit Smart. They say things like, "If you don't pay, we'll have you in court on Monday." or "If you don't pay the next step is to issue a warrant for your arrest." They will not give you any means (such as an address) to dispute the debt in writing. This is illegal under Fair Debt Collection Practices Act and is a violation of federal law. If they contact you, report them to your state attorney general or consumer affairs office IMMEDIATELY.