Don't Ever Give Out Information About Your Account if You Didn't Initiate the Call
Don't ever give any personal information during a call from your bank, cell phone company, etc. It doesn't matter how much information they have about your account that is accurate (which, in the post Equifax world, is easy to come by); it's all to lull you into a false sense of security. They might also try to instill some sense of urgency; don't fall for that either.
Instead, tell them that you will hang up and call them back. Or, don't pick up phone calls from numbers you don't recognize, and just let them leave a voicemail.
When Looking Up Company Phone Numbers, Don't Google It
Some scammers will put up fake sites that try to rank highly in search results for "company X phone number." Either go directly to the company's website, or in the case of a debit/credit card, call the number on the back of the card. Don't use the number left in a voicemail either; use the published phone number.
The IRS Won't Call You*
The IRS might call you in rare situations, but ONLY if they have initiated contact via mail first.
Sidenote: this is why every time you move, you should either file a change of address form with the IRS and your state's tax department, if applicable, or if tax filing season is close, file your taxes.