This is a fraudulent company. See this write up from Fox59 who talks about this very phone #. Don't pay them. Call the IRS directly if you have any worries. Someone from Stockton, CA would not be calling with the IRS. The IRS wouldn't make you wire transfer out of the country & the IRS would send letters before calling you....
Left message on answering machine. Neville (with Indian accent) from Department of Legal Affairs called and stated that I must call him back immediately so litigation matter can be resolved. Same number has called back the next 4 days without leaving a message.
I don't know why you WOULDN'T take it as a joke - debt is civil, not criminal, so no one is going to be arrested. Also, if you really were going to be arrested, the cops have a habit of just showing up. Block the caller and report them to the FTC, FBI and your state's Attorney General.