Check your phone’s recent call log for any hidden caller details
Contact your mobile carrier and ask whether they can trace the call
Use a call-tracing feature if your carrier provides one
Enable call blocking or spam protection apps that may identify unknown callers
Set your phone to silence or filter unknown callers
Ask the caller to leave a voicemail, then review the voicemail details
Report harassing or threatening calls to your carrier or local authorities
Use a reverse lookup service only if the number becomes visible later