Claimed to be IRS with unresolved case file. Second call within an hour (first from another number).

Got a call on my cellphone. Call ID only says NY, New York. I didn't answer, but they left a voicemail claiming to be IRS about a law suit being filed against me, and that I should call them. I have received a few of these calls on my landline. I know that the IRS doesn't call, but will send some sort of notice, but I still dialed the number anyway to see who would answer, and give them 'a piece of my mind' about scamming people and dishonesty. I know...I shouldn't call, I can't make them stop...but these scams really bother me. No answer. I have blocked this number.