my grandma just got a call and got super worried because the voice mail said that if she didn't call back she was going to face legal charges and they were going to do some unwanted stuff but we googled the number and it said that if it was important they would of sent you a letter or called your from a 00 number

Yes Melanie the IRS will never call you UNLESS you call them first. All correspondence will be done by good old US mail.
Good job looking out for grandma

I received this message today.  Bogus, I don't owe the IRS a thing...

"Very time sensitive. The very second you receive this message I need you to return the call as soon as possible to my department number 1-206-582-0749. I repeat 1-206-582-0749. If we don't receive your call. You will have to face hard and unwanted legal consequences including your social security number will be under state investigation and will be red flag and to avoid all legal consequences. You must call us as soon as possible because this is the last chance for the resolve of this serious case. Again this message is for you and this is Charles Wilson from criminal investigation Department of Internal Revenue Service. Goodbye and take care."