Creepy call

So I was at working at my high school today and I had my prep period last period of the day, so I was checking my texts from my sister who’s been watching my 8 month old daughter since yesterday since the babysitter had a family death and she was very close to the person. So she sends me the voicemail from the IRS saying we have to do something or we’ll be arrested abd charged and we did everything we were suppose too we didn’t not pay anything off. I really feel like it’s a scam.