Don't call back the number possibly being spoofed (i.e. using your Caller ID as the source of the callback number). Call an independently-listed number for the company, such as the phone number on the back of a credit or debit card. Using an independent number prevents any failures where the Caller ID correctly reports an attacker-controlled but plausible-sounding number.
For extra paranoia and safety, perform the callback from a separate phone line. That would avoid at least some of the more-targeted attacks involving a compromise of the victim's phone connection, which could potentially allow the attacker to redirect outgoing calls.
Don't call back the number possibly being spoofed (i.e. using your Caller ID as the source of the callback number). Call an independently-listed number for the company, such as the phone number on the back of a credit or debit card. Using an independent number prevents any failures where the Caller ID correctly reports an attacker-controlled but plausible-sounding number.
For extra paranoia and safety, perform the callback from a separate phone line. That would avoid at least some of the more-targeted attacks involving a compromise of the victim's phone connection, which could potentially allow the attacker to redirect outgoing calls.