I got two calls from this number, with messages to call immediately about this 'case'. I don't answer calls from numbers I don't recognize and I sure don't call them back. I sincerely doubt that the IRS would call at all hours of the day and night, as indicated by some of these messages, even IF they did make calls, which they don't! Please don't be fooled by these scammers--they want your information to steal your identity and everything you have.
They keep calling me my personal cell phone and leave an illegible voice message. It's starting to border on harassment. The FBI should investigate them. DO NOT CALL.