I've received two similar calls, one from 202-280-7709 and another from 281-898-6578. these must be scam. IRS wouldn't make such calls for any urgent matters.
Talked to the FBI. These IRS scams have risen 400% in the last few months. Report phone # to IRS and do not give these idiots any information. After giving them a hard time yesterday the idiots had the nerve to call me today and even asked for me by my first name. I advised them I reported the number to the IRS.