Open the Phone app
Tap Recents
Find the spam number
Tap the info icon next to the number
Scroll down
Tap Block this Caller
Tap Block Contact
Go to Settings
Tap Phone
Turn on Silence Unknown Callers
Go to Settings
Tap Phone
Tap Call Blocking & Identification
Enable any spam call blocking apps you have installed
Open the Messages app
Open the spam conversation
Tap the contact or number at the top
Tap Info
Tap Block this Caller
Go to Settings
Tap FaceTime
Block unwanted FaceTime callers the same way
Contact your carrier
Ask about spam call blocking services
Report spam numbers to your carrier or local authorities